The Act provided for the provinces of Spain to be established as multi-member districts in the Congress of Deputies,[2] with this regulation being maintained under the Spanish Constitution of 1978.

[3] Additionally, the Constitution requires for any modification of the provincial limits to be approved under an organic law, needing an absolute majority in the Cortes Generales.

[4] Voting is on the basis of universal suffrage, which comprises all nationals over 18 years of age and in full enjoyment of their political rights.

[10] 348 seats are elected using the D'Hondt method and a closed list proportional representation, with an electoral threshold of three percent of valid votes—which includes blank ballots—being applied in each constituency.

Also since 2011, parties, federations or coalitions that have not obtained a mandate in either chamber of the Cortes at the preceding election are required to secure the signature of at least 0.1 percent of electors in the aforementioned constituencies.