According to data from the 2002 Census of Population and Housing, Cabildo had 18,916 inhabitants; of these, 12,453 (65.8%) lived in urban areas and 6,463 (34.2%) in rural areas. At that time, there were 9,466 men and 9,450 women. The population grew 8.0% (1,396 persons) from the 1992 census count of 17,520.
As a commune, Cabildo is a third-level administrative division of Chile administered by a communal council, headed by an alcalde who is directly elected every four years. The 2008-2012 alcalde is Eduardo Cerda Lecaros. The communal council has the following members: