The 1964 United States Senate election in Maine was held on November 3, 1964. Incumbent Democrat Edmund Muskie was re-elected to a second term in office over Republican U.S. Representative Clifford McIntire. This was the first senate race for this particular seat in which the election was held in November and not September. This was the first time ever that an incumbent Democratic Senator from Maine was re-elected to a second full term.
Senator Muskie was unopposed for re-nomination.
Representative McIntire was unopposed for the Republican nomination.