- Bicameral parliament
- Chamber name: Congress of Deputies (Congreso de los Diputados)
- Members (lower house): 350
- Term: 4 years
- Constituencies: 50 multi-member (2 seats minimum per province, the rest allotted according to population) constituencies corresponding to the country's provinces; 2 single-member constituencies (North African enclaves of Ceuta and Melilla).
- Voting system: Mixed. Multi-member constituencies: blocked party lists and the d'Hondt system of proportional representation - each voter chooses one list of those made available in the constituency (province); single-member constituencies: simple majority vote.
- Voter requirements: 18 years of age; Spanish citizenship.
- Voting is not compulsory.
Election results 2011, main parties. NUTS 2
Field, B.N. 2009. The parliamentary election in Spain, March 2008. Electoral Studies, Vol. 28(1), 155-158.
Delgado, I & Nieto, L.L. 2009. Spain. European Journal of Political Research, Vol. 48(7-8), 1114-1119.
Inter-Parliamentary Union, PARLINE database on national parliaments
Ministerio Del Interior (Ministry of the Interior): http://www.elecciones.mir.es/