The prevalence (lifetime, 12-month, 1-month) of mental disorders, their relationship with sociodemographic features, and the use of services were investigated in the population aged 18 years or older living in the catchment area of a large hospital complex in the city of São Paulo, Brazil. A community survey was conducted in two boroughs of São Paulo, on 1,464 residents aged 18 years or older. The assessment of psychopathology was made by CIDI 1.1, yielding diagnoses according to ICD-10 for mood disorders, anxiety disorders, non-affective psychosis, substance use disorders, dissociative and somatoform disorders, and cognitive impairment. Of the total sample, 45.9 % had at least one lifetime diagnosis of mental disorder, 26.8 % in the year, and 22.2 % in the month prior to interview. The most prevalent disorders (lifetime, 12-month, and 1-month, respectively) were: nicotine dependence (25 %, 11.4 %, 9.3 %), any mood disorder (18.5 %, 7.6 %, 5 %) with depressive episode the most prevalent mood disorder (16.8 %, 7.1 %, 4.5 %), any anxiety disorder (12.5 %, 7.7 %, 6 %), somatoform disorder (6 %, 4.2 %, 3.2 %), and alcohol abuse/dependence (5.5 %, 4.5 %, 4 %). No gender differences were found in overall morbidity. Excluding substance use disorders, women had a higher risk for non-psychotic disorders. The presence of psychiatric diagnosis increased the use of services, with a low proportion of subjects seeking specialty mental care. Our results confirm the high prevalence of mental disorders in the community, similar to findings in other countries. A comparison with findings from other studies with similar methodology is made.