This was the very first election in an independent Republic of Singapore. The first Parliament was convened on 8 December 1965, four months after the country's separation from Malaysia. The by-election was precipated by the resignation of BS Member of Parliament Lim Huan Boon on 31 December 1965, who had opposed his party's boycott of Parliament and instruction to its MPs not to attend sittings. BS had denounced Singapore's independence as "phoney", stating that the decision to leave Malaysia should have been tabled in the legislature, and its members would bring their fight for democracy onto the streets. A day following his resignation, Lim was expelled by BS.

Writ of election: 3 January 1966 [Mon]
Nomination day: 8 January 1966 [Sat]
Polling day: 18 January 1966 [Tue]
Member swearing-in: 23 February 1966 [Wed]

Eligible voters: 13,209
Voter turnout: 11,346 (85.9%)

Election deposit: $500

Bukit Merah
Total seats = 1