Although poor partner support is a key risk factor for depression in pregnant and postpartum women, partners are not generally involved in treatment beyond psychoeducation. The aim of this "proof of concept" study was to test safety, acceptability, and feasibility of Partner-Assisted Interpersonal Psychotherapy (PA-IPT), an intervention that includes the partner as an active participant throughout treatment. Women more than 12 weeks estimated gestational age and less than 12 weeks postpartum were invited to participate if they fulfilled DSM-IV criteria for Major Depressive Disorder and reported moderate symptom severity (HAM-D(17) ≥16). The open trial included eight acute-phase sessions and a 6-week follow-up assessment. Ten couples completed the acute phase treatment and nine presented for a 6-week follow-up assessment. There were no study-related adverse events, and no women had symptomatic worsening from intake to Session Eight. All partners attended all sessions, no couples dropped out of treatment, and all reported positive treatment satisfaction at the conclusion of the study. Nine of ten women (90 %) met the criteria for clinical response (HAM-D(17) = 9) at the conclusion of acute phase treatment, and eight of the nine (89 %) presenting at a 6-week follow-up assessment met criteria for symptomatic recovery. Incorporating partners in the treatment of major depressive disorders during the perinatal period is safe, acceptable, and feasible, but needs further testing in a larger population to evaluate efficacy.