| Election Name: | 1972 United States Senate election in Illinois |
| Country: | Illinois |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1966 United States Senate election in Illinois |
| Previous Year: | 1966 |
| Next Election: | 1978 United States Senate election in Illinois |
| Next Year: | 1978 |
| Election Date: | November 7, 1972 |
| Image1: | Charles Percy (Illinois Blue Book Portrait 1971-1972).png |
| Nominee1: | Charles Percy |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 2,867,078 |
| Percentage1: | 62.21% |
| Nominee2: | Roman Pucinski |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 1,721,031 |
| Percentage2: | 37.35% |
| Map Size: | 300x300px |
| U.S. Senator | |
| Before Election: | Charles H. Percy |
| Before Party: | Republican Party (United States) |
| After Election: | Charles H. Percy |
| After Party: | Republican Party (United States) |
| Turnout: | 51.24% |
The 1972 United States Senate election in Illinois took place on November 7, 1972.[1] Incumbent Republican United States Senator Charles H. Percy sought re-election to the United States Senate. Percy was opposed by Democratic nominee Roman Pucinski, a United States Congressman from Illinois's 11th congressional district, whom he was able to defeat handily to win a second term., this was the last time a Republican was elected to the U.S. Senate from Illinois during a presidential election year, the last time an Illinois Republican won a Senate election by double digits, and the last time any candidate has swept every county in the state.
The primary (held on March 21) and general election coincided with those for House and state elections.[1]
Turnout in the primaries was 31.40%, with a total of 1,753,727 votes cast.[1]
Turnout during the general election was 51.24%, with 3,184,764 votes cast.[1]
Turnout in both the primary and general election was significantly less than those for coinciding statewide races.[1]
Congressman Roman Pucinski defeated Dakin Williams in the Democratic primary. Williams was a prosecutor who was the younger brother of playwright Tennessee Williams.
Incumbent Charles H. Percy was renominated without opposition in the Republican primary.