A second round of by-elections in the year - and the first time for multiple seats - took place to fill the vacancies that followed the resignations of another three BS Members of Parliament. Chio Cheng Thun and Kow Kee Seng resigned on 8 January 1966 and were expelled from BS six days later. S. T. Bani resigned from both his seat and the party on 9 January 1966. Walkover victories, not seen since the Legislative and City Council by-elections of 1952 and 1953 respectively, returned three PAP candidates without polls conducted.

Writ of election: 23 February 1966 [Wed]
Nomination day: 1 March 1966 [Tue]
Members swearing-in: 21 April 1966 [Thu]

Eligible voters: 36,573

Election deposit: $500

RESULTS
Chua Chu Kang	Crawford	Paya Lebar
Total seats = 3