Although the Senate was conceived as a territorial upper house, it has been argued by nationalist parties and the Spanish Socialist Workers' Party that it does not accomplish such a task because 208 out of 266 members of the Senate are elected by popular vote in each province, and only 58 are representatives appointed by the regional legislatures of autonomous communities.
Deși senatul a fost numit cameră superioară teritorială, partidele naționale și Partidul Socialist Muncitoresc Spaniol nu îl consideră astfel fiindcă 208 din cei 266 de membri sunt aleși prin vot popular și doar 58 revrezintă legislaturile autonome.