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

The Statute provided for the nine provinces in Castile and León—Ávila, Burgos, León, Palencia, Salamanca, Segovia, Soria, Valladolid and Zamora—to be established as multi-member districts in the Cortes of Castile and León, with this regulation being maintained under the 1987 regional electoral law.

Each constituency is entitled to an initial minimum of three seats, with one additional member per each 45,000 inhabitants or fraction greater than 22,500.

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

[5][6] 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.