| Harry Ross Papers | 1912-1962 | | LP000109 |
| Fred Ross Sr. Papers | 1954-1965 | | LP000862 |
| Robert Rossi Papers | 1969-1989 | | LP002132 |
| Herrick S. Roth Papers | 1948-1970 | | LP000424 |
| Jack Rugh Papers | 1942-1971 | | LP000473 |
| William A. Ryan Papers | 1968-1970 | | UP000578 |
| Gene Saari Papers | 1913-1979 | | LP001437 |
| Edward Sadlowski Papers | 1964-1976 | | LP000754 |
| Saginaw Federation of Labor Records | 1917-1941 | | LR000070 |
| Reverend Victor P. Salandini Papers | 1954-1973 | | LP000467 |
| Wilbert Salmi Papers | 1936 | | LP001490 |
| Carl Sandburg Tape Recordings | 1949-1963 | | UP000222 |
| George James Saul Manuscript | 1969 | | LP002401 |
| Clarence N. Sayen Papers | 1930-1965 | | LP000228 |
| Albert Sayer Papers | 1936-65 | | LP000395 |
| Emma Schaver Papers | 1910-2000, bulk 1923-1975 | | UP002185 |
| David S. Schick Papers | 1934-1969 | | LP000555 |
| Helen Schiff Papers | 1940-1967 | | LP001172 |
| M. B. Schnapper Papers | 1943-1946 | | LP000493 |
| Peter B. Schneider Papers | 1949-1955 | | LP000153 |
| Schools of the 21st Century Records | 1996-2004 | | UR001853 |
| Paul Schrade Papers | 1973 | | LP000632 |
| Bernard Schuck Papers | 1952–1979 | | LP000989 |
| Louis A. Schwartz Papers | 1957-1979 | | LP000926 |
| William M. Seabron Papers | 1935-1971 | | LP000511 |
| Robert Sedler Papers | 1985-1990 | | UP001833 |
| SEIU Administrative Services Department Records | 1974-1986, bulk 1982-1984 | | LR001886 |
| SEIU Communications Department Records | 1976-1987, bulk 1978-1987 | | LR001885 |
| SEIU District 925 Records | 1973-2004 | | LR001805 |
| SEIU Education and Support Fund Records | 1979-1984, bulk 1979-1980 | | LR001891 |
| SEIU Executive Office: David Sullivan Records | 1937-1973 | | LR001542_EOSullivan |
| SEIU Executive Office: George Hardy Records | 1934-1989 | | LR001542_Hardy |
| SEIU Executive Office: John Sweeney Records | 1921-1995 | | LR001542 |
| SEIU Executive Office: Microfilm | 1921-1955 | | LR001542_EOMicro |
| SEIU Executive Office: William McFetridge Records | 1936-1963 | | LR001542_McFet |
| SEIU Executive Vice President's Office: Patricia Ford Records | 1997-2005, bulk 2002-2004 | | LR002423 |
| SEIU Healthcare Division Records | 1986-1989 | | LR001889 |
| SEIU Historical Records | 1905-1996 | | LR001924 |
| SEIU International Affairs Records | 1985-2002, bulk 1992-1998 | | LR0001871 |
| SEIU International Jewelry Workers' Union Records | 1936-1991 | | LR001542_IJWU |
| SEIU International Vice-Presidents Records | 1938-1981 | | LR001542_IVP |
| SEIU Local 31-M Records | 1960-2005, bulk 1975-2002 | | LR001868 |
| SEIU Local 32B-32J Records | 1961-1994, bulk 1974-1981, 1986-1994 | | LR001893 |
| SEIU Local 535 Records | 1967-2003, bulk 1995-2003 | | LR002109 |
| SEIU Local 79 Records | 1952-1992 | | LR001728 |
| SEIU Morton H. Shapiro Papers | 1976-2004 | | LAV002404 |
| SEIU Organizing Department Records | 1970-1994, bulk 1985-1992 | | LR001888 |
| SEIU Public Relations Records | 1978-2003, bulk 1983-1995 | | LR001835 |
| SEIU Research Department Historical Records | 1916-1997 | | LR001542_RH |
| SEIU Research Department Records | 1930-1995, bulk 1946-1994 | | LR001884 |
| SEIU Retired Members Department Records | 1979-1989, bulk 1979-1980 | | LR001890 |
| SEIU Secretary-Treasurer's Office: Constitutions and By-Laws Records | circa 1920s-2002 | | LR001542_Bylaws |
| SEIU Secretary-Treasurer's Office: International Executive Board Records | 1921-1996 | | LR001542_IEB |
| SEIU Secretary-Treasurer's Office: Richard Cordtz Records | 1920-1995, bulk 1980-1992 | | LR001887 |
| SEIU Secretary-Treasurer's Office: Subject File Records | 1943-1985, bulk 1975-1984 | | LR001542_Subj |
| SEIU Secretary-Treasurer’s Office: Affiliate Officers Records | 1967-1987 | | LR001715 |
| William Seraile Papers | 1921-1922 | | LP000960 |
| Matthew and Elizabeth Serviss Fox Papers | 1918, 1921 | | LP000583 |
| Brendan Sexton Papers | 1938-1988 | | LP001046 |
| Ann Shafer Papers | 1950-1990, bulk 1960-1990 | | UP001480 |
| Leo D. Shaffer Papers | 1941-1954 | | LP000369 |
| Albert Shanker Papers | 1928-2003, bulk 1949-1968 | | LP001932 |
| Eugene Shafarman Papers | 1935-1978, bulk 1936-1940 | | LP001100 |
| Mark Sharwood Papers | 1974-1979, bulk 1977-1978 | | LP001220 |
| Warren Shear Papers | 1934 | | UP000215 |
| Horace Sheffield Papers | 1963-1977 | | LP000144 |
| George Shenkar Papers | 1947-1981, bulk 1947-1968 | | LP001430 |
| Lillian Sherwood Papers | 1943-1955 | | LP000360 |
| Carl Shier Papers | 1949-1966 | | LP000240 |
| A.G. Shultz Papers | 1937-1967 | | LP000322 |
| Irwin Silber Papers | 1886-1968 | | LP000412 |
| Paul Silver Papers | 1946-1963 | | LP000172 |
| Ted F. Silvey Papers | 1936-1969 | | LP000625 |
| Morag McLeod Simchak Papers | 1955-1976, bulk 1961-1975 | | LP000905 |
| Charles J. Simone Papers | 1943 | | LP000992 |
| Bud and Hazel Simons Papers | 1937-1962 | | LP000160 |
| William Simons Papers | 1906-1980s, bulk 1950s-1980s | | LP001761 |
| Luther Slinkard Papers | circa 1930-1969 | | LP000386 |
| Blanding Sloan Papers | 1928-1939 | | LP000674 |
| Ernest Smith Papers | 1962-1977, bulk 1964-1971 | | LP000906 |
| George Smith Papers | 1948-1955 | | LP000670 |
| Howard R. Smith Papers | 1939-1962 | | LP000806 |
| Joseph Smith Papers | 1908-1932 | | LP000854 |
| Norman Smith Papers | 1935-1964, bulk 1935-1946 | | LP000574 |
| Stanton and Nancy Smith Papers | 1938-1942 | | LP000544 |
| Sydney D. Smith Papers | 1960-1986 | | LP001397 |
| Joseph Snyder Papers | 1958-1968 | | UP000275 |
| South Eastern Michigan Gay and Lesbian Association Records | 1976-2011, bulk 1982-1988 | | UR002537 |
| Southeast Michigan Council of Governments (SEMCOG) Records | 1947-2006 | | UR001008 |
| Joseph Spaniolo Papers | 1973-1981 | | LP001101 |
| Nemmy Sparks Papers | 1942-1973, bulk 1955-1973 | | LP000617_Sparks |
| Roy Speth Papers | 1934-1936 | | LP00043F |
| Paul Sporn Papers | circa 1930-1949 | | UP001700 |
| William C. Stark Papers | 1975-1992 | | LP000970 |
| Thomas J. Starling Papers | 1937-1970 | | LP000988 |
| Paul Ste-Marie Papers | 1939-1943 | | LP001686 |
| Nicolaas Steelink Papers | 1912-1953 | | LP000140 |
| Lionel Stephan Papers | 1931-1932 | | LP000410 |
| Thomas W. Stephens Papers | 1978-2003 | | UP001747 |
| Marc Stepp Papers | 1940-2000, bulk 1970-1988 | | LP001440 |