The electoral system uses the D'Hondt method and a closed-list proportional representation, with a minimum threshold of three percent.

The constituency was created as per the Statute of Autonomy for the Basque Country of 1979 and was first contested in the 1980 regional election.

Each constituency is allocated a fixed number of 25 seats each, to provide for an equal representation of the three provinces in Parliament as required under the regional Statute.

[2][3][4] Voting is on the basis of universal suffrage, which comprises all nationals over eighteen, registered in the Basque Country and in full enjoyment of their political rights.

[2][3][4] The use of the D'Hondt method may result in a higher effective threshold, depending on the district magnitude.