Admissions to treatment for heroin abuse have increased in recent years among the adolescent and young adult population, yet few studies have described whether, and to what extent, young heroin users differ from their non heroin-using peers. This exploratory study presents quantitative and qualitative data obtained from lifetime heroin and non heroin-using adolescents and young adults in a long-term, step-down therapeutic community. Self-report data from the Global Appraisal of Individual Needs (GAIN) were obtained from 22 lifetime heroin and 33 non heroin users on admission to residential treatment and 12 months later. Ethnographic interviews (n = 27) were conducted with heroin users at all stages of treatment. Results indicate that lifetime heroin users had greater polysubstance use and lower self-efficacy scores (i.e., confidence to resist relapse) on admission to treatment than non heroin users, and though improved, heroin users' self-efficacy scores remained lower than those of non heroin users at the 12 month follow-up. Ethnographic data suggested that adolescents who had used heroin "hit bottom" before entering treatment and credited treatment with providing the opportunity to change their lives. The overall comparability of treatment outcomes between the heroin and non heroin using groups shows that adolescents and young adult heroin users can achieve similar outcomes in an age-appropriate therapeutic community treatment setting.