[3][4] Five by-elections were held on 6 April 1978, following the simultaneous resignations of five Conservative councillors on 13 February 1978.

[5][6][7] The Hitchin Bearton by-election was triggered by the resignation of Conservative councillor David Ingram, citing business reasons.

The Hitchin Highbury by-election was triggered by the resignation of Conservative councillor Stephen Arthur Whaley, who had moved away from the district.

The Ward 13 by-election was triggered by the resignation of Conservative councillor John Stapleton, who had moved away from the district.

The Ward 14 by-election was triggered by the resignation of Conservative councillor Ian Rose, citing business reasons.