The politics of the county had been transformed following the victory of Gwynfor Evans at the Carmarthen by-election in the previous year.
This led to an increased number of Plaid Cymru candidates although they had limited success.
The Labour losses included Douglas Hughes, leader of the Council and a member since 1928.
Of the contests that took place, the most notable were in Llanelli town where the leader of the authority, Alderman Douglas Hughes ( a member since 1928) and his wife Alderman Loti Rhys Hughes (a member since 1946) were both defeated.
Labour lost seats at Burry Port to the Independents and at Kidwelly and Pembrey to Plaid Cymru.