OBJECTIVE:Recent studies show an alarming rate of alcohol and drug use among university students. The objective of this study was to assess the level of association between lifestyle and socioeconomic status and the prevalence of alcohol, tobacco, medicine, and "illicit drug" use in the last 12 months among university students. METHODS:The sample included 926 undergraduate students in the Biology Department of a university in São Paulo who completed an anonymous, self-applied questionnaire in 2000 and 2001. Anova and Chi-square tests were applied to verify the correlation between substance use and variables. RESULTS:Among students who reported having a religion, alcohol consumption was 83.1%, tobacco use 20.7%, and "illicit drugs" 24.6% during this period. Among students who reported not having a religion, reported alcohol use was higher in the last 12 months: alcohol (89.3%), tobacco (27.7%) and "illicit drugs" (37.7%). Monthly family income was related to alcohol and "illicit drug" use (p<0.001 for both). The students who used tobacco and "illicit drugs" reported more free time during the week than students who didn't smoke during the period of time analyzed (p=0.033 and p=0.008, respectively). CONCLUSIONS:Psychoactive drug use was common among students, indicating a need for policies to be implemented with the goal of reducing consumption. Students with higher family income and without religion should be considered to be at higher risk for alcohol and drug use among this group.