1978 United States Senate election in Maine

1978 United States Senate election in Maine

← 1972 November 7, 1978 1984 →
 
Nominee William Cohen William Hathaway Hayes Gahagan
Party Republican Democratic Independent
Popular vote 212,294 127,327 27,824
Percentage 56.59% 33.94% 7.42%

County results
Cohen:      50–60%      60–70%      70–80%

U.S. senator before election

William Hathaway
Democratic

Elected U.S. Senator

William Cohen
Republican

The 1978 United States Senate election in Maine was held on November 7, 1978. Incumbent Democratic U.S. Senator William Hathaway ran for re-election to a second term, but was defeated by William Cohen, the Republican U.S. Representative from Maine's 2nd congressional district. This is the last time a Senator from Maine lost re-election.

No incumbent Senator has lost by such a large margin since Hathaway's 22.65-point loss, though James Abdnor in 1980, John Boozman in 2010, and Tommy Tuberville in 2020 all received larger percentages of the vote than Cohen's 56.59% against incumbent Senators.