There were 2 by elections held in 1977 where both People's Action Party's Members of Parliament, and had died suddenly, which vacates Radin Mas and Bukit Merah respectively. Through co-operation within the opposition camp, no 3 corner / multiple corner fights were shown in both by-elections.
First 1977 By Election (May)[]
With the demise of who was the then incumbent of Radin Mas, it sets the first by election in 1977 with the polling day on 14 May 1977 and the nomination day was set on 4 May 1977.
Second 1977 By Election (July)[]
With the demise of who was the then incumbent of Bukit Merah, it sets the second by election in 1977 with the polling day on 23 July 1977 and the nomination day was set on 13 July 1977.
Election deposit[]
The election deposit was set at $1200. Similar with previous elections, the election deposit will be forfeited if the particular candidate had failed to secure at least 12.5% or one-eighth of the votes.