The constituency was created as per the 1985 Treaty of Accession and was first contested in the 1987 European election in Spain.

[1][2][3][4][5] The European Parliament Committee on Constitutional Affairs proposed on 23 January 2018 an increase of the number of seats allocated to Spain from 54 to 59 after Brexit has taken place, a proposal that first needs to be adopted by the Parliament, then approved by the European Council, to be made effective.

[6][7] Voting is on the basis of universal suffrage, which comprises all nationals and non-national European citizens over eighteen and in full enjoyment of their political rights.

[10][11] However, the use of the D'Hondt method may result in an effective threshold depending on the district magnitude.

Parties, federations and coalitions are allowed to replace this requirement with the signature of at least 50 elected officials—deputies, senators, MEPs or members from the legislative assemblies of autonomous communities or from local city councils—.