Objectives - To quantify students’ use of tobacco, alcohol, and cannabis and to identify the sociodemographic and socioeconomic factors associated with these uses. Methods - Survey of first-year students enrolled in 2005–2006 at universities in the Provence-Alpes-Côte d’Azur region, conducted via self-administered questionnaire and telephone. Analysis of factors associated with these behaviors separately among girls and boys using simple and then multiple logistic regressions. Results - 1,723 students responded (response rate: 71%, average age 19 years). Among them, 23% of males and 25% of females smoke daily, while regular use of alcohol and cannabis is less frequent. However, 31% of males and 17% of females reported at least one episode of intoxication in the past month. Among both male and female students, alcohol and cannabis use were not associated with age, whereas tobacco use increased with age. Other factors associated with psychoactive substance use differed by gender. Among boys, living with a partner, living away from family, and being enrolled in a liberal arts program; and among girls, living with a partner, having a paid job or financial support from family, and being enrolled in a liberal arts program were associated with increased use of one or more psychoactive substances. Conclusion - This study suggests a plateau in alcohol and cannabis use and an increase in tobacco use with age among students. Overall, few socioeconomic factors were associated with the use of these substances. Among boys, our results suggest a relative social homogeneity in drug use at the onset of adulthood. (R.A.)