A by-election was held in the Dáil constituency of Donegal South-West in Ireland on Friday, 13 May 1983. It followed the death of Fianna Fáil TD Clement Coughlan on 1 February 1983.
On 19 April 1983, the writ of election to fill the vacancy was issued. The by-election was held on 13 May 1983., and the by-election was won by the Fianna Fáil candidate Cathal Coughlan, brother of the deceased TD.
Cathal Coughlan died on 21 June 1986. On 22 October 1986, a Fianna Fáil motion to issue the writ, opposed by the Fine GaelâÂÂLabour government, was rejected by a vote of 81 to 82.
No by-election was held to fill the vacancy, but Cathal Coughlan's daughter, Mary Coughlan, was elected for the constituency at the 1987 general election.