Background: While mentorship programs, which connect adolescents with adults to whom they can turn to for help and advice, are proliferating in an attempt to prevent high-risk behaviors in teenagers, there are few data to show that mentorship actually makes a difference., Objective: To determine if there is an association between having an adult mentor and high-risk behaviors in adolescents., Hypothesis: Adolescents who have an adult mentor would be less likely to engage in high-risk behaviors than those without an adult mentor., Design: Cross-sectional study. A self-administered, anonymous questionnaire was developed to assess demographics, involvement in risk behaviors, and the prevalence of a mentor in the life of a young person., Participants: A convenience sample of 294 adolescents, seen consecutively (93% of those approached), receiving outpatient medical care. Participants were predominantly female (68%), of mixed race/ethnicity, aged between 12 and 23 years (mean +/- SD age, 16.9 +/- 2.4), and from diverse socioeconomic backgrounds., Setting: An adolescent health service in a suburban community-based teaching hospital., Main Outcome Measures: Adolescent smoking, alcohol and drug use, sexual practices, and weapon carrying., Results: Adolescents with mentors were significantly less likely to participate in 4 of the 5 measured risk behaviors: ever carrying a weapon (odds ratio, 0.41; P< or =.01), illicit drug use in the past 30 days (odds ratio, 0.44; P< or =.01), smoking more than 5 cigarettes per day (odds ratio, 0.54; P< or =.05), and sex with more than 1 partner in the past 6 months (odds ratio, 0.56; P< or =.05). No significant difference was found with alcohol use (> or =3 drinks in the past 30 days)., Conclusion: A strong positive relationship was found between adolescents having an adult mentor and decreased participation in 4 of the 5 risk behaviors evaluated.