The 1958 United States Senate elections in Arizona took place on November 4, 1958. Incumbent Republican U.S. Senator Barry Goldwater ran for reelection to a second term, and defeated former U.S. Senator, and then-Governor, Ernest McFarland in the general election. The election was a virtual rematch from 1952, where Goldwater defeated McFarland by a narrow margin. Goldwater had attributed the win to the unpopularity of President Harry S. Truman and popular Wisconsin Senator Joseph McCarthy endorsing his campaign.
This would be McFarland's final run for statewide office, as he became Chief Justice of the Arizona Supreme Court in 1968 before retiring from public service.