RESUMEN
Background: Family is an important protective factor in the prevention of risk behaviors in Chilean adolescents. Aim To determine the prevalence of risk and protective factors and behaviors in Chilean students, and to study the association between family functioning and adolescent risk behaviors. Material and methods: Descriptive cross sectional study of 815 adolescents aged 15 ± 2 years (51 percent male), studying 7th to 12th grade in three educational facilities in Santiago, Chile. They answered the Adolescent Risk Behavior Score, adapted from the Adolescent Health Survey and the "How is your family" survey of the Pan American Health Organization. Results: Tobacco, alcohol and marihuana consumption was reported by 31 percent, 27 percent and 24 percent of students, respectively. Twelve percent reported being sad all the time, 23 percent being desperate and 13 percent being anxious. Forty four percent have had a sexual intercourse. The risk to have these behaviors was greater in adolescents who perceive their families as dysfunctional. Conclusions: In this sample, there was a high prevalence of risk behaviors, emotional symptoms and premature sexual intercourse. The risk of having these behaviors is higher among students who perceive their families as dysfunctional. The study emphasizes the protective function of family in the prevention of risk behaviors in Chilean students.