Biscay is one of the 59 constituencies (Spanish: circunscripciones) represented in the Senate of Spain, the upper chamber of the Spanish parliament, the Cortes Generales. The constituency elects four senators. Its boundaries correspond to those of the Spanish province of Biscay. The electoral system uses an open list partial block voting, with electors voting for individual candidates instead of parties. Electors can vote for up to three candidates.