PAGE 1
000 A000000 06/30/2006
000 C000000 0000831655
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 6.1
000 J000000 A
001 A000000 MASSMUTUAL PARTICIPATION INVESTORS
001 B000000 811-5531
001 C000000 4132261000
002 A000000 1500 MAIN STREET, SUITE 600
002 B000000 SPRINGFIELD
002 C000000 MA
002 D010000 01115
002 D020000 0001
003 000000 N
004 000000 N
005 000000 N
006 000000 N
007 A000000 N
007 B000000 0
007 C010100 1
007 C010200 2
007 C010300 3
007 C010400 4
007 C010500 5
007 C010600 6
007 C010700 7
007 C010800 8
007 C010900 9
007 C011000 10
008 A000001 BABSON CAPITAL MANAGEMENT LLC
008 B000001 A
008 C000001 801-241
008 D010001 SPRINGFIELD
008 D020001 MA
008 D030001 01115
008 D040001 0001
012 A000001 SHAREHOLDER FINANCIAL SERVICES, INC.
012 B000001 84-1817
012 C010001 DENVER
012 C020001 CO
012 C030001 80217
012 C040001 3673
013 A000001 KPMG LLP
013 B010001 BOSTON
013 B020001 MA
013 B030001 02110
013 B040001 2371
PAGE 2
014 A000001 BABSON CAPITAL SECURITIES INC
014 B000001 8-47589
015 A000001 CITIBANK, N.A.
015 B000001 C
015 C010001 NEW YORK
015 C020001 NY
015 C030001 10043
015 E010001 X
018 000000 Y
019 A000000 Y
019 B000000 2
019 C000000 CIPIINVEST
020 A000001 ALLEN & COMPANY INC.
020 B000001 13-4132953
020 C000001 16
020 A000002 JEFFERIES & CO., INC.
020 B000002 94-1737782
020 C000002 1
020 A000003 ICAP CORPORATES, LLC
020 B000003 13-3858854
020 C000003 0
020 A000004 GOLDMAN, SACHS & CO.
020 B000004 13-5108880
020 C000004 0
020 A000005 BANC OF AMERICA SECURITIES LLC
020 B000005 56-2058405
020 C000005 0
020 A000006 WACHOVIA SECURITIES LLC
020 B000006 34-1542819
020 C000006 0
020 A000007 CREDIT SUISSE SECURITIES (USA) LLC
020 B000007 13-5659485
020 C000007 0
020 A000008 LIQUIDNET, INC.
020 B000008 13-4095933
020 C000008 0
020 A000009 JP MORGAN CHASE
020 B000009 13-4994650
020 C000009 0
020 A000010 LEHMAN BROTHERS INC.
020 B000010 13-2518466
020 C000010 0
021 000000 18
022 A000001 GOLDMAN, SACHS & CO.
022 B000001 13-5108880
022 C000001 70193
022 D000001 0
022 A000002 JP MORGAN CHASE
022 B000002 13-4994650
022 C000002 54613
022 D000002 0
PAGE 3
022 A000003 MERRILL, LYNCH, PIERCE, FENNER & SMITH, INC.
022 B000003 13-5674085
022 C000003 45926
022 D000003 849
022 A000004 FIRST BOSTON CORP.
022 B000004 13-5659485
022 C000004 27527
022 D000004 504
022 A000005 CITIGROUP
022 B000005 13-3214963
022 C000005 20106
022 D000005 600
022 A000006 SHEARSON LEHMAN AMERICAN EXPRESS
022 B000006 13-2518466
022 C000006 13605
022 D000006 742
022 A000007 TERRA RENEWAL SERVICES, INC.
022 B000007 71-0774612
022 C000007 1367
022 D000007 0
022 A000008 FOWLER HOLDING, INC.
022 C000008 1335
022 D000008 0
022 A000009 ONTARIO DRIVE & GEAR LTD.
022 C000009 1333
022 D000009 0
022 A000010 RADIAC ABRASIVES, INC.
022 C000010 1329
022 D000010 0
023 C000000 251450
023 D000000 6269
024 000000 N
025 A000001 DELETE
025 D000001 0
025 D000002 0
025 D000003 0
025 D000004 0
025 D000005 0
025 D000006 0
025 D000007 0
025 D000008 0
026 A000000 N
026 B000000 Y
026 C000000 N
026 D000000 Y
026 E000000 N
026 F000000 Y
026 G010000 N
026 G020000 N
026 H000000 N
027 000000 N
PAGE 4
028 A010000 0
028 A020000 0
028 A030000 0
028 A040000 0
028 B010000 0
028 B020000 0
028 B030000 0
028 B040000 0
028 C010000 0
028 C020000 0
028 C030000 0
028 C040000 0
028 D010000 0
028 D020000 0
028 D030000 0
028 D040000 0
028 E010000 0
028 E020000 0
028 E030000 0
028 E040000 0
028 F010000 0
028 F020000 0
028 F030000 0
028 F040000 0
028 G010000 0
028 G020000 0
028 G030000 0
028 G040000 0
028 H000000 0
030 A000000 0
030 B000000 0.00
030 C000000 0.00
031 A000000 0
031 B000000 0
032 000000 0
033 000000 0
035 000000 0
036 B000000 0
038 000000 0
042 A000000 0
042 B000000 0
042 C000000 0
042 D000000 0
042 E000000 0
042 F000000 0
042 G000000 0
042 H000000 0
043 000000 0
044 000000 0
045 000000 Y
046 000000 N
PAGE 5
047 000000 Y
048 000000 0.900
048 A010000 0
048 A020000 0.000
048 B010000 0
048 B020000 0.000
048 C010000 0
048 C020000 0.000
048 D010000 0
048 D020000 0.000
048 E010000 0
048 E020000 0.000
048 F010000 0
048 F020000 0.000
048 G010000 0
048 G020000 0.000
048 H010000 0
048 H020000 0.000
048 I010000 0
048 I020000 0.000
048 J010000 0
048 J020000 0.000
048 K010000 0
048 K020000 0.000
049 000000 N
050 000000 N
051 000000 N
052 000000 N
053 A000000 N
054 A000000 Y
054 B000000 Y
054 C000000 Y
054 D000000 N
054 E000000 N
054 F000000 N
054 G000000 Y
054 H000000 Y
054 I000000 N
054 J000000 Y
054 K000000 N
054 L000000 N
054 M000000 Y
054 N000000 N
054 O000000 Y
055 A000000 N
055 B000000 N
056 000000 Y
057 000000 N
058 A000000 N
059 000000 Y
060 A000000 Y
PAGE 6
060 B000000 Y
061 000000 0
062 A000000 Y
062 B000000 0.0
062 C000000 0.0
062 D000000 0.0
062 E000000 0.0
062 F000000 0.0
062 G000000 0.0
062 H000000 0.0
062 I000000 7.0
062 J000000 0.0
062 K000000 0.0
062 L000000 0.0
062 M000000 0.0
062 N000000 0.0
062 O000000 0.0
062 P000000 81.5
062 Q000000 0.0
062 R000000 16.6
063 A000000 0
063 B000000 5.7
064 A000000 Y
064 B000000 Y
065 000000 N
066 A000000 Y
066 B000000 N
066 C000000 N
066 D000000 N
066 E000000 N
066 F000000 N
066 G000000 Y
067 000000 N
068 A000000 N
068 B000000 N
069 000000 N
070 A010000 Y
070 A020000 N
070 B010000 Y
070 B020000 Y
070 C010000 N
070 C020000 N
070 D010000 N
070 D020000 N
070 E010000 N
070 E020000 N
070 F010000 N
070 F020000 N
070 G010000 N
070 G020000 N
070 H010000 N
PAGE 7
070 H020000 N
070 I010000 N
070 I020000 N
070 J010000 Y
070 J020000 Y
070 K010000 N
070 K020000 N
070 L010000 Y
070 L020000 Y
070 M010000 N
070 M020000 N
070 N010000 Y
070 N020000 N
070 O010000 Y
070 O020000 Y
070 P010000 N
070 P020000 N
070 Q010000 N
070 Q020000 N
070 R010000 N
070 R020000 N
071 A000000 22852
071 B000000 21384
071 C000000 122959
071 D000000 17
072 A000000 6
072 B000000 5834
072 C000000 490
072 D000000 0
072 E000000 0
072 F000000 576
072 G000000 0
072 H000000 0
072 I000000 8
072 J000000 0
072 K000000 0
072 L000000 51
072 M000000 61
072 N000000 0
072 O000000 0
072 P000000 367
072 Q000000 0
072 R000000 48
072 S000000 0
072 T000000 0
072 U000000 0
072 V000000 0
072 W000000 14
072 X000000 1125
072 Y000000 0
072 Z000000 5199
PAGE 8
072AA000000 8626
072BB000000 334
072CC010000 0
072CC020000 694
072DD010000 2343
072DD020000 0
072EE000000 0
073 A010000 0.2400
073 A020000 0.0000
073 B000000 0.0000
073 C000000 0.0000
074 A000000 3827
074 B000000 0
074 C000000 9199
074 D000000 103059
074 E000000 2774
074 F000000 16880
074 G000000 0
074 H000000 0
074 I000000 4652
074 J000000 868
074 K000000 0
074 L000000 1874
074 M000000 13
074 N000000 143146
074 O000000 0
074 P000000 292
074 Q000000 12000
074 R010000 0
074 R020000 0
074 R030000 0
074 R040000 921
074 S000000 0
074 T000000 129933
074 U010000 9777975
074 U020000 0
074 V010000 13.29
074 V020000 0.00
074 W000000 0.0000
074 X000000 6068
074 Y000000 0
075 A000000 0
075 B000000 124190
076 000000 14.85
077 A000000 Y
077 O000000 Y
077 Q010000 N
077 Q020000 N
077 Q030000 N
078 000000 N
080 C000000 0
PAGE 9
081 B000000 0
082 B000000 0
083 B000000 0
084 B000000 0
086 A010000 34
086 A020000 459
086 B010000 0
086 B020000 0
086 C010000 0
086 C020000 0
086 D010000 0
086 D020000 0
086 E010000 0
086 E020000 0
086 F010000 0
086 F020000 0
087 A010000 SHARES OF BENEFICIAL INTEREST
087 A020000 576299101
087 A030000 MPV
088 A000000 Y
088 B000000 N
088 C000000 N
088 D000000 N
SIGNATURE JAMES M. ROY
TITLE V.P. AND C.F.O.
EXHIBIT INDEX TO FORM N-SAR
OF MASSMUTUAL PARTICIPATION INVESTORS
FOR SEMI-ANNUAL PERIOD ENDED JUNE 30, 2006
EXHIBIT NO. DESCRIPTION
77O Transactions Effected Pursuant to Rule 10F-3