Rio de Janeiro State has one of the largest networks of psychiatric hospitals in Brazil, one of them the Dr. Eiras Paracambi Hospital (CSDE-P). In late 2000, the current Mental Health Advisory Division of the Rio de Janeiro State Health Department conducted a clinical and psychosocial census of patients hospitalized in the CSDE-P. The hospital population consisted of 1,494 individuals, the majority men (53.4%), single (81.6%), working-age (66.4%), and with limited schooling (only 11.5% with a complete primary education or more). Most had been in hospital for at least two years (77.6%), received visits from relatives (60.5%), but did not have hospital leave (73.8%). The predominant diagnoses were schizophrenia (53.6%) and mental retardation (26.4%). The main therapeutic approach was psychiatric (84.1%). Only 13.3% took part in systematic activities during the day, although 36% were in a condition to do so. CSDE-P is a mega-hospital where most patients have precarious social links, demanding treatment strategies which take this characteristic into account.