Objective: To assess the smoking behaviors, beliefs about the risks of smoking, and exposure to ETS among adolescents in Juarez, Mexico. Methods: A cross-sectional study was conducted with sixth-grade students (N=506), aged 11-13 years old, attending 6 randomly selected schools. Schools were classified by school setting and SES. Results: Students attending a low SES school setting were more likely to have smoked (P less than 0.01), be current smokers (Pless than 0.01), be exposed to ETS at home and in public (P less than 0.01) than were students attending a middle or high SES school. Conclusion: Smoking interventions should target students attending school in low SES settings.