The objective of this study was to examine the prevalence and characteristics of adult psychotropic medication use in São Paulo, Brazil. Information on lifetime and 12-month psychotropic medication use, and psychiatric status was obtained from a representative sample of 2000 adults aged 18–65 years in São Paulo, Brazil. Lifetime and 12-month use of psychotropic medications was 16.8 and 7.1%, respectively. Of the 22.8% of patients with current psychiatric problems, 29.5% reported lifetime use and 15.8% (5.6% of the sample) reported 12-month use (anxiolytics: 2.7%, antidepressants: 1.8%, alternative medicines: 0.9%, antipsychotics: 0.4%, mood stabilizers: 0.4%, hypnotics: 0.3%; multiple class use occurred). The most frequent prescribers were psychiatrists and general practitioners. Determinants of use included identification as a psychiatric case (four-fold increased odds), being female (three-fold increase), age (4–5% per additional year), and lower odds if married. Education, employment status, and birth in São Paulo were not associated with use. Income did not affect anxiolytic use, but antidepressant and alternative medicine use was associated with higher income. These results show that psychotropic drug use was comparatively low. Only 15.8% of patients with psychiatric problems reported recent psychotropic use. Comparable with other studies, use was greater among women and increased with age.