Mayo West was a parliamentary constituency represented in Dáil Éireann, the lower house of the Irish parliament or Oireachtas from 1969 to 1997.
The method of election was proportional representation by means of the single transferable vote (PR-STV).
Following the resignation of Fianna Fáil TD Pádraig Flynn on his appointment as EU Commissioner, a by-election was held on 9 June 1994.
Following the death of Fine Gael TD Henry Kenny, a by-election was held on 12 November 1975.
The seat was won by the Fine Gael candidate Enda Kenny, son of the deceased TD.