The mayor was in turn elected by the plenary assembly, with a legal clause providing for the candidate of the most-voted party to be automatically elected to the post in the event no other candidate was to gather an absolute majority of votes.

Local councillors were elected using the D'Hondt method and a closed list proportional representation, with an electoral threshold of five percent of valid votes—which included blank ballots—being applied in each local council.

Councillors were allocated to municipal councils based on the following scale: Additionally, municipalities below 25 inhabitants, as well as those having traditionally adopted it, were to be organized through the open council system (Spanish: régimen de concejo abierto), in which electors would directly vote for the local major.

Most deputations were indirectly elected by local councillors from municipalities in each judicial district.

Seats were allocated to provincial deputations based on the following scale: Island councils and the foral deputations of Biscay, Gipuzkoa and Navarre were elected directly by electors under their own, specific electoral regulations.