Objective: A substantial number of patients with major depressive disorder (MDD) do not respond to treatment, and recurrence rates remain high. The purpose of this study was to examine a history of severe childhood abuse as a moderator of response following a 16-week acute treatment trial, and of recurrence over a 12-month follow-up. Method: Participants included 203 adult outpatients with MDD (129 women; age 18-60). The design was a 16-week single-center randomized, open label trial of interpersonal psychotherapy, cognitive-behavioral therapy, or antidepressant medication, with a 12-month naturalistic follow-up, conducted at a university psychiatry center in Canada. The main outcome measure was Hamilton Depression Rating Scale scores at treatment end point. Childhood maltreatment was assessed at the completion of treatment using an interview-based contextual measure of childhood physical, sexual, and emotional abuse. Multiple imputation was adopted to estimate missing values. Results: Patients with severe maltreatment were significantly less likely to respond to interpersonal psychotherapy than to cognitive-behavioral therapy or medication (OR = 3.61), whereas no differences among treatments were found in those with no history of maltreatment (ORs less than 1.50). Furthermore, maltreatment significantly predicted a shorter time to recurrence over follow-up across treatment conditions (OR = 3.04). These findings were replicated in the sample with complete case data. Conclusions: Patients with a history of childhood abuse may benefit more from antidepressant medication or cognitive-behavioral therapy than from interpersonal psychotherapy. However, these patients remain vulnerable to recurrence regardless of treatment modality. (Contains 3 footnotes, 2 figures and 2 tables.)