To estimate the prevalence of lifetime use of crack cocaine and to assess associations with violent and sexual behaviors in young adults selected from the general population of Pelotas, Southern Brazil. This cross-sectional population-based study included 1,560 participants aged 18-24 years. The use of alcohol and other substances, including crack cocaine, was assessed using the alcohol, smoking and substance involvement screening test. Other variables included violent behaviors, firearm possession, and sexual risk behaviors. The frequency of antisocial personality disorder was also investigated. Associations were analyzed using a crude model and models adjusted for sex, social class, and the use of snorted cocaine. Lifetime prevalence of crack cocaine use was 2.51 %, and it was higher among males and individuals coming from more vulnerable social classes (D or E). In the final multivariate models, lifetime use of crack cocaine was associated with episodes of aggression and firearm possession, as well as with a higher chance of not having used condom in the last sexual intercourse. In less conservative models, crack cocaine use was associated with other violent and sexual risk behaviors. The strong association observed between lifetime use of crack cocaine and different violent and sexual risk behaviors underscores relevant characteristics of people who use crack cocaine. Improving our understanding of possible causal chains leading to such associations should be a priority in future studies.