To design a treatment manual and adherence measure for attachment-based family therapy (ABFT) for adolescent depression and to collect pilot data on the treatment's efficacy.Over a period of 2 years, 32 adolescents meeting criteria for major depressive disorder (MDD) were randomly assigned to 12 weeks of ABFT or a 6-week, minimal-contact, waitlist control group. The sample was 78% female and 69% African American; 69% were from low-income, inner-city communities.At post-treatment, 81% of the patients treated with ABFT no longer met criteria for MDD, in contrast with 47% of patients in the waitlist group. Mixed factorial analyses of variance revealed that, compared with the waitlist group, patients treated with ABFT showed a significantly greater reduction in both depressive and anxiety symptoms and family conflict. Of the 15 treated cases assessed at the follow-up, 13 patients (87%) continued to not meet criteria for MDD 6 months after treatment ended.ABFT appears to be a promising treatment and worthy of further development.