The analysis of the baseline and 1-year follow-up data determined that significant effects were achieved in students' negative attitudes toward drug abuse, intentions to avoid substance abuse, peer resistance skills, self-efficacy, perceived susceptibility, knowledge about side effects of substances, and level of self-control. The evaluation concludes that using life-skills training can improve self-control skills and contribute to substance abuse prevention. The dominant aim of the intervention was to provide participants with social resistance skills. Activities were designed and implemented based on students' educational needs, training resistance, and social and communication skills. Instruction techniques included role playing and group discussion. The program also aimed to increase students' knowledge of the side effects and consequences of substance use. In addition, students developed cognitive-behavioral skills that could be used to enhance self-esteem. These included self-control skills, decisionmaking skills, assertiveness techniques, peer resistance, and drug refusal skills. Other program components included health education and behavioral rehearsal. Two schools were randomly selected from all-male high schools within Tehran's No. 10 District, one of the most populated urban regions in Iran. Of the 203 male 10th graders enrolled at the 2 schools, 189 participated in the study. The evaluation methodology included survey instruments with 55 items designed to measure perceived susceptibility, self-efficacy, self-control, knowledge about the side effects of drugs, attitude against drug abuse, peer-resistance skills, and behavioral intentions. 4 tables and 25 references