UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM N-Q

QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED MANAGEMENT INVESTMENT COMPANY

Investment Company Act file number      811-09571     

Nuveen Senior Income Fund

(Exact name of registrant as specified in charter)

     333 West Wacker Drive, Chicago, Illinois 60606     
(Address of principal executive offices) (Zip code)

Kevin J. McCarthy—Vice President and Secretary
     333 West Wacker Drive, Chicago, Illinois 60606     
(Name and address of agent for service)

Registrant’s telephone number, including area code:      312-917-7700     

Date of fiscal year end:        7/31      

Date of reporting period:    4/30/2007   

Form N-Q is to be used by management investment companies, other than small business investment companies registered on Form N-5 (§§ 239.24 and 274.5 of this chapter), to file reports with the Commission, not later than 60 days after the close of the first and third fiscal quarters, pursuant to rule 30b1-5 under the Investment Company Act of 1940 (17 CFR 270.30b1-5). The Commission may use the information provided on Form N-Q in its regulatory, disclosure review, inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-Q, and the Commission will make this information public. A registrant is not required to respond to the collection of information contained in Form N-Q unless the Form displays a currently valid Office of Management and Budget (“OMB”) control number. Please direct comments concerning the accuracy of the information collection burden estimate and any suggestions for reducing the burden to the Secretary, Securities and Exchange Commission, 450 Fifth Street, NW, Washington, DC 20549-0609. The OMB has reviewed this collection of information under the clearance requirements of 44 U.S.C. § 3507.

 

 

Nuveen Senior Income Fund (NSL)
April 30, 2007

						Weighted
Principal						Average
Amount (000)				Description (1)		Coupon		Maturity (3)		Ratings (4)		Value
				Variable Rate Senior Loan Interests – 144.8% (92.5% of Total Investments) (2)
				Aerospace & Defense – 2.2% (1.4% of Total Investments)
$	2,521			Mid-Western Aircraft Systems Inc., Term Loan B		7.105%		12/31/11		BB+		$	2,535,442
	2,403			Vought Aircraft Industries, Inc., Term Loan		7.830%		12/22/11		Ba2			2,423,589
	545			Vought Aircraft Industries, Inc., Tranche B, Letter of Credit		7.822%		12/22/10		Ba2			549,545
	5,469			Total Aerospace & Defense									5,508,576
				Airlines – 4.1% (2.6% of Total Investments)
	2,000			Delta Airlines Inc., Second Lien Term Loan, WI/DD		TBD		TBD		B			2,028,750
	2,000			Delta Airlines Inc., Term Loan, WI/DD		TBD		TBD		Ba2			2,010,938
	2,000			Northwest Airlines Inc., Term Loan		7.320%		7/19/08		BBB-			2,009,376
	4,400			United Air Lines Inc., Delayed Draw, Term Loan		7.375%		2/01/14		B+			4,406,875
	10,400			Total Airlines									10,455,939
				Auto Components – 5.7% (3.6% of Total Investments)
	4,224			Federal-Mogul Corporation, Term Loan A, (7)		7.570%		2/24/04		N/R			4,209,968
	5,551			Federal-Mogul Corporation, Term Loan B, (7)		7.820%		2/24/05		N/R			5,536,271
	500			Gen Tek Inc., Term Loan B		7.340%		2/28/11		Ba3			502,031
	1,860			Gen Tek Inc., Term Loan B		7.356%		12/28/11		Ba3			1,867,092
	2,000			Goodyear Tire & Rubber Company, Second Lien Term Loan		7.100%		4/30/14		Ba2			2,010,315
	1,479			Metalforming Technologies, Inc., Term Loan A, (7) (8)		0.000%		9/30/07		N/R			281,039
	575			Metalforming Technologies, Inc., Term Loan B, (PIK), (7) (8)		0.000%		9/30/07		N/R			109,299
	16,189			Total Auto Components									14,516,015
				Building Products – 6.3% (4.0% of Total Investments)
	884			Atrium Companies Inc., Term Loan		8.518%		5/31/12		B1			880,931
	2,000			Building Materials Corporation of America, Second Lien Term Loan		11.125%		9/15/14		B			1,983,333
	1,995			Building Materials Corporation of America, Term Loan		8.188%		2/22/14		BB-			1,986,521
	2,547			Euramax Holdings Inc., Term Loan B		8.375%		6/29/12		B1			2,546,916
	1,950			Nortek, Inc., Term Loan B		7.365%		8/27/11		Ba2			1,958,288
	2,448			Stile Acquisition Corporation, Canadian Term Loan		7.350%		4/05/13		BB-			2,399,340
	2,452			Stile Acquisition Corporation, Term Loan B		7.350%		4/05/13		BB-			2,403,427
	1,990			TFS Acquisition, Term Loan		8.850%		8/11/13		B+			2,004,925
	16,266			Total Building Products									16,163,681
				Capital Markets – 0.7% (0.4% of Total Investments)
	1,777			Ameritrade Holdings Corporation, Term Loan B		6.820%		12/31/12		Ba1			1,782,834
				Chemicals – 3.8% (2.4% of Total Investments)
	1,600			Celanese Holdings, LLC, Term Loan C		7.099%		4/02/14		BB-			1,610,250
	400			Celanese Holdings, LLC, Credit Linked Deposit		5.320%		4/02/14		BB-			402,563
	2,985			Hexion Specialty Chemicals, Inc., Term Loan C		7.875%		5/05/13		Ba3			3,010,071
	762			Huntsman International LLC, Term Loan		7.070%		8/16/12		Ba1			764,565
	1,980			ISP Chemco Inc., Term Loan		7.290%		2/16/13		BB-			1,994,319
	1,960			Rockwood Specialties Group, Inc., Term Loan E		7.355%		7/30/12		Ba2			1,978,253
	9,687			Total Chemicals									9,760,021
				Commercial Services & Supplies – 4.3% (2.7% of Total Investments)
	2,370			Acco Brands, Term Loan B		7.110%		8/17/12		Ba1			2,390,739
	1,457			Allied Waste North America, Inc., Letter of Credit		7.073%		1/15/12		BB			1,465,497
	3,285			Allied Waste North America, Inc., Term Loan B		7.097%		1/15/12		BB			3,303,079
	1,000			Rental Services Corporation, Term Loan		8.857%		11/30/13		B-			1,017,000
	2,000			Williams Scotsman, Inc., Term Loan B		6.820%		6/28/10		BB			1,999,375
	681			Workflow Management, Inc., Term Loan		9.355%		11/30/11		BB-			680,438
	10,793			Total Commercial Services & Supplies									10,856,128
				Communications Equipment – 0.6% (0.4% of Total Investments)
	427			Valassis Communications, Inc., Delayed Draw, Term Loan, (5) (9)		1.000%		3/02/14		Ba2			(267	)
	1,573			Valassis Communications, Inc., Term Loan B		7.100%		3/02/14		Ba2			1,576,939
	2,000			Total Communications Equipment									1,576,672
				Construction & Engineering – 0.7% (0.4% of Total Investments)
	1,687			Maxim Crane Works, Term Loan		7.326%		1/28/10		N/R			1,689,790
				Containers & Packaging – 5.4% (3.4% of Total Investments)
	457			Bluegrass Container Company LLC, 1st Lien Term Loan		7.589%		6/30/13		BB-			462,784
	1,515			Bluegrass Container Company, LLC, Delayed Draw, Second Lien		10.320%		12/31/13		BB-			1,546,212
	485			Bluegrass Container Company, LLC, Delayed Draw, Second Lien		10.320%		12/31/13		B-			494,788
	1,528			Bluegrass Container Company, LLC, Term Loan B		7.591%		6/30/13		BB-			1,546,674
	7,522			Graham Packaging Company, L.P., Term Loan B		7.625%		2/14/10		B1			7,576,633
	437			Smurfit-Stone Container Corporation, Deposit-Funded Commitment		7.748%		11/01/11		Ba2			440,446
	996			Smurfit-Stone Container Corporation, Term Loan B		7.531%		11/01/11		Ba2			1,004,903
	532			Smurfit-Stone Container Corporation, Term Loan C		7.546%		11/01/11		Ba2			536,175
	190			Smurfit-Stone Container Corporation, Tranche C-1		7.375%		11/01/11		Ba2			191,773
	13,662			Total Containers & Packaging									13,800,388
				Diversified Consumer Services – 0.9% (0.5% of Total Investments)
	2,163			West Corporation, Term Loan		7.750%		10/24/13		B+			2,181,266
				Diversified Financial Services – 0.6% (0.4% of Total Investments)
	1,500			UPC Financing Partnership, Term Loan K2		7.370%		12/31/13		Ba3			1,503,214
				Diversified Telecommunication Services – 6.1% (3.9% of Total Investments)
	2,000			Cequel Communications LLC., Term Loan B		7.349%		11/05/13		B+			2,000,250
	2,000			Crown Castle International Corporation, Term Loan		6.893%		1/26/14		BB+			2,006,016
	1,965			Intelsat Corporation, Term Loan		7.349%		7/01/13		Ba2			1,981,092
	2,000			Intelsat Corporation, Unsecured Term Loan		7.860%		2/01/14		BB			2,009,643
	2,267			Level 3 Communications Incorporated, Term Loan		7.605%		3/13/14		B1			2,276,938
	5,000			Qwest Corporation, Term Loan B		6.950%		6/30/10		BB			5,151,043
	5,000			WCI Capital Corporation, Term Loan B, (7) (8)		0.000%		9/30/07		N/R			200,000
	20,232			Total Diversified Telecommunication Services									15,624,982
				Electric Utilities – 2.0% (1.3% of Total Investments)
	709			Astoria Generating Company, Term Loan B		7.340%		2/23/13		BB-			714,246
	4,444			Calpine Corporation DIP Term Loan		7.590%		3/29/09		N/R			4,472,684
	556			Calpine Corporation DIP Revolver, (5) (9)		0.250%		3/29/09		N/R			(8,333	)
	5,709			Total Electric Utilities									5,178,597
				Electrical Equipment – 1.6% (1.0% of Total Investments)
	2,256			Mueller Group, Inc., Term Loan		7.348%		10/03/12		BB-			2,273,770
	1,539			Sensus Metering Systems Inc., Term Loan B-1		7.364%		12/17/10		Ba3			1,546,826
	167			Sensus Metering Systems Inc., Term Loan B-2		7.361%		12/17/10		Ba3			167,573
	3,962			Total Electrical Equipment									3,988,169
				Electronic Equipment & Instruments – 0.8% (0.5% of Total Investments)
	1,985			Sensata Technologies B.V., Term Loan		7.105%		4/27/13		BB-			1,986,297
				Energy Equipment & Services – 1.1% (0.7% of Total Investments)
	2,885			Dresser-Rand Group, Inc., Term Loan		10.000%		10/31/13		B1			2,900,377
				Food & Staples Retailing – 0.7% (0.5% of Total Investments)
	1,851			Jean Coutu Group Inc. Term Loan B		7.875%		7/30/11		BB-			1,855,004
				Food Products – 2.3% (1.5% of Total Investments)
	465			Dole Foods Company Inc., Deposit-Funded Commitment		7.356%		4/12/13		Ba3			465,181
	1,036			Dole Foods Company Inc., Term Loan B		7.541%		4/12/13		Ba3			1,036,191
	3,453			Dole Foods Company Inc., Term Loan C		7.456%		4/12/13		Ba3			3,453,968
	862			Michael Foods, Inc., Term Loan B		7.360%		11/21/10		Ba3			865,606
	5,816			Total Food Products									5,820,946
				Gas Utilities – 0.8% (0.5% of Total Investments)
	2,000			Energy Transfer Partners LP, Term Loan		7.080%		2/08/12		BBB-			2,015,357
				Health Care Providers & Services – 12.0% (7.7% of Total Investments)
	5,294			Community Health Systems, Inc., Term Loan		7.100%		8/19/11		BB-			5,313,690
	3,292			Davita Inc., Term Loan B		6.842%		10/05/12		Ba1			3,304,886
	1,995			HCA, Inc., Term Loan		7.600%		11/17/13		BB			2,018,184
	2,000			Health Management Associates, Term Loan		7.100%		2/28/14		Ba2			2,010,208
	1,985			HealthSouth Corporation, Term Loan		7.847%		3/10/13		B+			2,001,128
	464			IASIS Healthcare, LLC, Delayed Term Loan, WI/DD		TBD		TBD		Ba2			465,571
	124			IASIS Healthcare, LLC, Letter of Credit, WI/DD		TBD		TBD		Ba2			124,152
	1,357			IASIS Healthcare, LLC, Term Loan, WI/DD		TBD		TBD		Ba2			1,362,571
	3,940			LifeCare Holdings Inc., Term Loan B		7.600%		8/01/12		B1			3,913,405
	2,152			Psychiatric Solutions Inc., Term Loan B		7.092%		12/01/12		Ba3			2,158,934
	2,940			Select Medical Corporation, Term Loan		7.349%		2/24/12		Ba2			2,935,156
	4,896			Vanguard Health Holding Company, LLC, Replacement Term Loan		7.600%		9/23/11		Ba3			4,933,652
	30,439			Total Health Care Providers & Services									30,541,537
				Hotels, Restaurants & Leisure – 12.7% (8.3% of Total Investments)
	4,950			24 Hour Fitness Worldwide, Inc., Term Loan B		7.850%		7/01/09		Ba3			4,984,031
	1,788			Ameristar Casinos, Inc., Term Loan B		6.820%		11/10/12		BB+			1,789,495
	778			CBRL Group, Inc., Term Loan B-1		6.860%		4/27/13		BB			779,791
	122			CBRL Group, Inc., Term Loan B-2, Delayed Draw, (5) (9)		0.750%		4/27/13		BB			(51	)
	3,930			CCM Merger, Inc., Term Loan B		7.350%		7/13/12		Ba3			3,952,130
	1,985			Cedar Fair LP, Term Loan		7.320%		8/30/12		BB-			2,006,091
	2,836			Intrawest Corporation, Term Loan		9.250%		12/31/07		N/R			2,843,018
	1,955			Isle of Capri Casinos, Inc., Term Loan		7.070%		2/04/11		Ba1			1,970,151
	3,940			Penn National Gaming, Inc., Term Loan B		7.114%		10/03/12		BB			3,972,013
	2,000			Pinnacle Entertainment Inc., Term Loan		7.320%		12/14/11		BB-			2,017,708
	1,000			Quiznos Sub, Term Loan C		11.100%		11/05/13		N/R			1,018,542
	130			Seminole Gaming, Term B-1 Delayed Draw, (5)		2.844%		3/05/14		BBB-			32,470
	437			Seminole Gaming, Term B-2 Delayed Draw		6.875%		3/05/14		BBB-			437,520
	433			Seminole Gaming, Term B-3 Delayed Draw		6.875%		3/05/14		BBB-			433,469
	2,719			Travelport, Term Loan		7.850%		8/23/13		Ba3			2,745,551
	268			Travelport, Letter of Credit		7.850%		8/23/13		Ba3			270,312
	427			Venetian Casino Resort, LLC Term Loan B		7.090%		6/15/11		BB-			429,528
	2,073			Venetian Casino Resort, LLC, Term Loan		7.090%		6/15/11		BB-			2,083,213
	998			Worldspan LP, Term Loan		8.600%		12/07/13		Ba3			1,002,612
	32,769			Total Hotels, Restaurants & Leisure									32,767,594
				Household Durables – 2.1% (1.4% of Total Investments)
	4,478			Shea Homes Inc., Term Loan		7.320%		10/27/11		N/R			4,432,725
	1,006			William Carter Company, Term Loan B		6.846%		7/14/12		BB			1,006,420
	5,484			Total Household Durables									5,439,145
				Household Products – 2.3% (1.5% of Total Investments)
	1,901			Prestige Brands, Inc., Term Loan B		7.634%		4/06/11		Ba3			1,912,442
	3,979			Solo Cup Company, Term Loan		8.847%		2/27/11		B1			4,047,262
	5,880			Total Household Products									5,959,704
				Independent Power Producers & Energy Traders – 0.4% (0.3% of Total Investments)
	671			Covanta Energy Corporation, Term Loan B		6.875%		2/09/14		Ba2			672,363
	329			Covanta Energy Corporation, Letter of Credit		6.775%		2/09/14		Ba2			329,517
	1,000			Total Independent Power Producers & Energy Traders									1,001,880
				Insurance – 2.4% (1.5% of Total Investments)
	5,963			Conseco, Inc., Term Loan		7.320%		10/10/13		BB-			5,998,046
				Internet Software & Services – 1.2% (0.8% of Total Investments)
	2,992			Riverdeep Interactive Learning Ltd., Term Loan		8.100%		12/20/13		B1			3,015,693
				IT Services – 3.2% (2.0% of Total Investments)
	2,985			Dealer Computer Service, Term Loan		7.350%		10/26/12		Ba2			3,001,791
	5,131			SunGard Data Systems Inc., Term Loan B		7.360%		2/28/14		Ba3			5,181,547
	8,116			Total IT Services									8,183,338
				Leisure Equipment & Products – 1.1% (0.7% of Total Investments)
	2,734			Bombardier Recreational Products, Term Loan		7.860%		6/28/13		BB			2,755,539
				Machinery – 3.5% (2.2% of Total Investments)
	3,178			Navistar International, Term Loan		8.610%		1/31/12		BB-			3,226,105
	1,156			Navistar International Synthetic Letter of Credit		8.208%		1/19/12		BB-			1,173,129
	1,995			Oshkosh Truck Corporation, Term Loan		7.100%		12/06/13		BB			2,003,417
	557			Rexnord Corporation, Incremental Term Loan		7.580%		7/19/13		Ba2			561,835
	1,934			Rexnord Corporation, Term Loan		7.858%		7/19/13		Ba2			1,951,051
	8,820			Total Machinery									8,915,537
				Media – 22.6% (14.6% of Total Investments)
	4,500			American Media Operations, Inc., Term Loan C		8.450%		1/30/13		B1			4,532,814
	1,111			Blockbuster, Inc., Term Loan A		8.377%		8/20/09		B1			1,115,601
	1,663			Blockbuster, Inc., Term Loan B		8.631%		8/20/11		B1			1,683,146
	1,965			Cablevision Systems Corporation, Incremental Term Loan		7.084%		3/29/13		BB			1,974,245
	1,985			Carmike Cinemas Inc., Term Loan		8.590%		5/19/12		B1			2,008,394
	1,000			Charter Communications Operating, LLC, Term Loan A		7.850%		9/06/14		B1			1,002,084
	1,000			Charter Communications Operating, LLC, Term Loan		7.350%		9/06/14		B1			999,766
	3,437			Dex Media West, LLC, Term Loan B		6.852%		3/09/10		Ba1			3,443,507
	2,993			Idearc Inc., Term Loan		7.350%		11/17/14		BB+			3,015,800
	2,963			Metro-Goldwyn-Mayer Studios, Inc., Term Loan B		8.600%		4/08/12		B+			2,969,257
	4,975			Neilsen Finance LLC, Term Loan B		7.610%		8/09/13		Ba3			5,024,233
	1,912			Philadelphia Newspapers, Term Loan		8.100%		6/29/13		N/R			1,923,841
	5,910			Primedia Inc., Term Loan		7.570%		9/30/13		B			5,914,001
	2,282			R. H. Donnelley Inc., Term Loan D-2		6.851%		6/30/11		Ba1			2,286,164
	4,586			Regal Cinemas Corporation, Term Loan		7.100%		10/27/13		Ba2			4,606,240
	1,567			Sun Media Corporation, Term Loan B		7.105%		2/07/09		Baa3			1,571,582
	483			Univision Communications, Delayed Draw, Term Loan, (5) (9)		1.000%		9/29/14		Ba3			(371	)
	2,000			Univision Communications, Second Lien Term Loan		7.820%		3/29/09		B3			2,002,083
	7,517			Univision Communications, Term Loan		7.605%		9/15/14		Ba3			7,511,013
	1,500			UPC Broadband Holding BV, Term Loan J2		7.370%		3/29/13		Ba3			1,503,214
	2,900			WMG Acquisition Corp., Term Loan		7.359%		2/28/11		Ba2			2,915,134
	58,249			Total Media									58,001,748
				Metals & Mining – 3.7% (2.4% of Total Investments)
	1,995			Aleris International, Term Loan		7.375%		12/19/11		B+			2,002,065
	1,876			Amsted Industries Incorporated, Delayed Draw, Term Loan		7.350%		4/05/11		BB-			1,880,759
	2,582			Amsted Industries Incorporated, Term Loan B		7.350%		4/05/13		BB-			2,591,270
	1,035			Freeport McMoran Copper and Gold, Term Loan		7.070%		3/19/14		Baa3			1,039,452
	1,979			John Maneely Company, Term Loan		8.611%		12/08/11		B+			1,985,622
	9,467			Total Metals & Mining									9,499,168
				Multi-Utilities – 1.6% (1.0% of Total Investments)
	2,860			NRG Energy Inc., Term Loan		7.350%		2/01/13		Ba1			2,885,472
	1,183			NRG Energy Inc., Credit-Linked Deposit		7.350%		2/01/13		Ba1			1,192,754
	4,043			Total Multi-Utilities									4,078,226
				Oil, Gas & Consumable Fuels – 3.5% (2.2% of Total Investments)
	301			Coffeyville Resources LLC, Letter of Credit		8.249%		5/10/10		B+			304,981
	1,549			Coffeyville Resources LLC., Term Loan		8.350%		12/28/13		B+			1,570,507
	1,000			El Paso Corporation, Letter of Credit		7.320%		7/31/11		Ba1			1,006,094
	774			Targa Resources Inc., Synthetic Letter of Credit		7.475%		10/31/12		B+			780,423
	3,177			Targa Resources Inc., Term Loan B		7.356%		10/31/12		B+			3,202,988
	2,000			Venoco Inc, Term Loan		9.875%		3/30/11		B-			2,021,250
	8,801			Total Oil, Gas & Consumable Fuels									8,886,243
				Paper & Forest Products – 3.4% (2.2% of Total Investments)
	1,013			Boise Cascade Corporation, Term Loan D		7.070%		3/29/11		BB			1,017,632
	1,555			Georgia-Pacific Corporation, Term Loan B-2		7.090%		12/20/12		Ba2			1,564,448
	3,950			Georgia-Pacific Corporation, Term Loan B		7.091%		12/20/10		Ba2			3,973,961
	2,086			NewPage Corporation, Term Loan B		7.625%		5/02/11		Ba2			2,106,726
	8,604			Total Paper & Forest Products									8,662,767
				Pharmaceuticals – 1.2% (0.8% of Total Investments)
	865			Stiefel Laboratories Inc, Delayed Draw, Term Loan		7.605%		12/28/13		Ba3			873,253
	1,000			Stiefel Laboratories Inc, Second Lien Term Loan		10.355%		6/15/13		B-			1,023,750
	1,130			Stiefel Laboratories Inc, Term Loan		7.605%		12/28/13		Ba3			1,141,697
	2,995			Total Pharmaceuticals									3,038,700
				Real Estate Investment Trust – 1.6% (1.0% of Total Investments)
	3,990			Landsource Community Development, Term Loan		8.070%		2/27/13		BB+			4,018,991
				Real Estate Management & Development – 2.9% (1.8% of Total Investments)
	3,721			Capital Automotive LP., Term Loan		7.070%		12/16/10		BB+			3,757,628
	3,500			LNR Property Corporation, Term Loan B		8.110%		7/12/11		B+			3,524,374
	7,221			Total Real Estate Management & Development									7,282,002
				Semiconductors & Equipment – 1.3% (0.8% of Total Investments)
	1,358			Advanced Micro Devices, Term Loan B		7.340%		12/31/13		BB-			1,361,961
	1,995			Freescale Semiconductor, Term Loan		7.110%		3/30/14		Baa3			2,000,663
	3,353			Total Semiconductors & Equipment									3,362,624
				Specialty Retail – 8.0% (5.1% of Total Investments)
	983			Burlington Coat Factory Warehouse Corporation, Term Loan		7.610%		5/28/11		B			978,386
	995			CSK Automotive Corporation, Term Loan		8.353%		6/30/12		Ba3			1,010,553
	3,897			Michaels Stores Inc., Term Loan		8.125%		10/31/13		B2			3,932,605
	1,318			Micro Warehouse, Inc., Term Loan B, (7) (8) (10)		0.000%		1/30/07		N/R			39,534
	3,979			Norwood Promotional Products, Term Loan A		11.625%		8/16/09		N/R			4,128,514
	5,993			Norwood Promotional Products, Term Loan B		6.000%		8/16/11		N/R			5,363,806
	995			Sally Beauty, Term Loan		7.860%		11/16/13		BB-			1,004,052
	4,000			TRU 2005 RE Holding Co. I, Inc., Term Loan		8.320%		12/09/08		B3			4,036,876
	22,160			Total Specialty Retail									20,494,326
				Textiles Apparel & Luxury Goods – 1.8% (1.1% of Total Investments)
	4,530			Visant Holding Corporation, Term Loan C		7.330%		7/29/10		B+			4,557,908
				Trading Companies & Distributors – 1.6% (1.0% of Total Investments)
	2,000			Ashtead Group Public Limited Company, Term Loan B		7.125%		8/31/11		BB			2,000,000
	393			Brenntag Holdings, Acquisition Facility		7.887%		1/20/14		B1			395,182
	1,607			Brenntag Holdings, Term Loan B2		7.887%		1/20/14		B1			1,626,108
	4,000			Total Trading Companies & Distributors									4,021,290
$	377,643			Total Variable Rate Senior Loan Interests (cost $374,487,916)									369,646,259

Principal
Amount (000)				Description (1)		Coupon		Maturity		Ratings (4)		Value
				Corporate Bonds – 9.1% (5.8% of Total Investments)
				Electronic Equipment & Instruments – 2.0% (1.3% of Total Investments)
$	5,000			NXP BV, Floating Rate Note, 2.750% plus three-month LIBOR, 144A		8.105%		10/15/13		BB+		$	5,187,500
				Hotels, Restaurants & Leisure – 1.0% (0.6% of Total Investments)
	2,400			Park Place Entertainment		8.875%		9/15/08		Ba1			2,499,000
				Media – 1.8% (1.2% of Total Investments)
	2,000			Cablevision Systems Corporation, Floating Rate Note, 4.500% plus six-month LIBOR, Series B 144A		9.860%		4/01/09		B+			2,130,000
	2,500			Primedia Inc., Floating Rate Note, 5.375% plus three-month LIBOR, 144A		10.730%		5/15/10		B			2,590,625
	4,500			Total Media									4,720,625
				Paper & Forest Products – 0.8% (0.5% of Total Investments)
	2,000			Verso Paper Holdings LLC., Floating Rate Note, 3.750% plus three-month LIBOR, 144A		9.105%		8/01/14		B			2,070,000
				Semiconductors & Equipment – 0.2% (0.1% of Total Investments)
	500			Avago Technologies Finance Pte. Ltd., Floating Rate Note, 5.500% plus three-month LIBOR, 144A		10.855%		6/01/13		B			525,000
				Textiles Apparel & Luxury Goods – 0.8% (0.5% of Total Investments)
	2,000			HanesBrands Inc., Floating Rate Note, 3.375% plus six-month LIBOR, 144A		8.735%		12/15/14		B2			2,065,000
				Wireless Telecommunication Services – 2.5% (1.6% of Total Investments)
	6,000			Dobson Communications Corporation, Floating Rate Note, 4.250% plus three-month LIBOR		9.605%		10/15/12		Caa1			6,210,000
$	22,400			Total Corporate Bonds (cost $22,281,573)									23,277,125

Shares				Description (1)								Value
				Common Stocks – 0.7% (0.4% of Total Investments)
				Auto Components – 0.0% (0.0% of Total Investments)
	511			Gen Tek Inc.,								$	16,740
	279,642			Metalforming Technologies Inc., (7) (8) (10)								–
				Total Auto Components									16,740
				Building Products – 0.7% (0.4% of Total Investments)
	34,834			Armstrong World Industries Inc.,									1,776,545
				Total Common Stocks (cost $1,393,369)									1,793,285

Shares				Description (1)								Value
				Warrants – 0.1% (0.0% of Total Investments)
	545			Gen Tek Inc., Warrant								$	25,750
	268			Gen Tek Inc., Warrant									11,859
	5,672			Reliant Energy Inc.									91,886
				Total Warrants (cost $40,254)									129,495

Principal
Amount (000)				Description (1)		Coupon		Maturity				Value
				Short-Term Investments – 2.0% (1.3% of Total Investments)
$	5,213			Repurchase Agreement with Fixed Income Clearing		4.900%		5/01/07				$	5,213,359
				Corporation, dated 4/30/07, repurchase price $5,214,069,
				collateralized by $3,915,000, U.S. Treasury Bonds,
				8.000%, due 11/15/21, value $5,324,400
				Total Short-Term Investments (cost $5,213,359)									5,213,359
				Total Investments (cost $403,416,471) – 156.7%									400,059,523
				Borrowings Payable – (40.4)% (6)									(103,000,000	)
				Other Assets Less Liabilities – 1.7%									4,164,976
				Preferred Shares, at Liquidation Value – (18.0)%									(46,000,000	)
				Net Assets Applicable to Common Shares – 100%								$	255,224,499

(1)		All percentages shown in the Portfolio of Investments are based on net assets applicable to Common shares unless otherwise noted.
(2)		Senior Loans in which the Fund invests generally pay interest at rates which are periodically adjusted by reference to a base short-term, floating lending rate plus an assigned fixed rate. These floating lending rates are generally (i) the lending rate referenced by the London Inter-Bank Offered Rate (“LIBOR”), or (ii) the prime rate offered by one or more major United States banks.
		Senior Loans may be considered restricted in that the Fund ordinarily is contractually obligated to receive approval from the Agent Bank and/or Borrower prior to the disposition of a Senior Loan.
(3)		Senior Loans generally are subject to mandatory and/or optional prepayment. Because of these mandatory prepayment conditions and because there may be significant economic incentives for a Borrower to prepay, prepayments of Senior Loans may occur. As a result, the actual remaining maturity of Senior Loans held may be substantially less than the stated maturities shown.
(4)		Ratings: Using the higher of Standard & Poor’s or Moody’s rating. Ratings below BBB by Standard & Poor’s Group or Baa by Moody’s Investor Service, Inc. are considered to be below investment grade.
(5)		Position or portion of position represents an unfunded Senior Loan commitment outstanding at April 30, 2007. At April 30, 2007, the Fund had unfunded Senior Loan commitments of $1,684,679.
(6)		Borrowings Payable as a percentage of total investments is (25.7)%.
(7)		At or subsequent to April 30, 2007, this issue was under the protection of the Federal Bankruptcy Court.
(8)		Non-income producing. Non-income producing, in the case of a loan, generally denotes that the issuer has defaulted on the payment of principal or interest or has filed for bankruptcy.
(9)		Negative value represents unrealized depreciation on Senior Loan commitment at April 30, 2007.
(10)		Investment valued at fair value using methods determined in good faith by, or at the discretion of, the Board of Trustees.
N/R		Not rated.
WI/DD		Purchased on a when-issued or delayed delivery basis.
144A		Investment is exempt from registration under Rule 144A of the Securities Act of 1933, as amended. These investments may only be resold in transactions exempt from registration which are normally those transactions with qualified institutional buyers.
TBD		Senior Loan purchased on a when-issued or delayed-delivery basis. Certain details associated with this purchase are not known prior to the settlement date of the transaction. In addition, Senior Loans typically trade without accrued interest and therefore a weighted average coupon rate is not available prior to settlement. At settlement, if still unknown, the Borrower or counterparty will provide the Fund with the final weighted average coupon rate and maturity date.
(PIK)		In lieu of cash payment, interest accrued on “Payment in Kind” investment increases principal outstanding.

The following information is presented on an income tax basis. Differences between amounts for financial statement and federal income tax purposes are primarily due to the treatment of paydown gains and losses and timing differences in recognizing certain gains and losses on investment transactions.

At April 30, 2007, the cost of investments was $403,416,471.

Gross unrealized appreciation and gross unrealized depreciation of investments at April 30, 2007, were as follows:

Gross unrealized:
Appreciation		$	5,308,617
Depreciation			(8,665,565	)
Net unrealized appreciation (depreciation) of investments		$	(3,356,948	)

Item 2. Controls and Procedures.

	a.		The registrant’s principal executive and principal financial officers, or persons performing similar functions, have concluded that the registrant’s disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended (the “1940 Act”) (17 CFR 270.30a-3(c))) are effective, as of a date within 90 days of the filing date of this report that includes the disclosure required by this paragraph, based on their evaluation of the controls and procedures required by Rule 30a-3(b) under the 1940 Act (17 CFR 270.30a-3(b)) and Rule 13a-15(b) or 15d-15(b) under the Securities Exchange Act of 1934 (17 CFR 240.13a-15(b) or 240.15d-15(b)).
	b.		There were no changes in the registrant’s internal control over financial reporting (as defined in Rule 30a-3(d) under the 1940 Act (17 CFR 270.30a-3(d)) that occurred during the registrant’s last fiscal quarter that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 3. Exhibits.

File as exhibits as part of this Form a separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the 1940 Act (17 CFR 270.30a-2(a)), exactly as set forth below: EX-99 CERT Attached hereto.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

(Registrant) Nuveen Senior Income Fund               

Date June 29, 2007

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

Date June 29, 2007

Date June 29, 2007