The 1928 United States Senate elections in Arizona took place on November 6, 1928. Incumbent Democratic U.S. Senator
Henry F. Ashurst ran for reelection to a fourth term, defeating Republican nominee former U.S. Senator
Ralph H. Cameron in the general election. Cameron was defeated in the previous election year, in 1926, by then-U.S. Congressman
Carl T. Hayden, leading Cameron to decide to challenge Ashurst in order to return to the United States Senate.