Little is known about the relative benefits of psychotherapy, medication, and combined treatment as continuation therapies for chronic forms of major depressive disorder (MDD) after a positive response to acute treatment. We hypothesize that combined treatment would demonstrate superior continuation phase outcomes compared to either monotherapy, as evidenced by lower relapse rates and greater rates of improvement from partial to full remission. We report 16-week continuation phase outcomes for 324 patients who had participated in either the acute phase of a randomized multicenter trial of nefazodone, Cognitive Behavioral Analysis System of Psychotherapy (CBASP), or combination therapy (COMB) for chronic forms of MDD. Patients entering the continuation phase had either fully or partially remitted after 12 weeks of acute phase treatment. The primary efficacy measure was the 24-item Hamilton Rating Scale for Depression. For patients in remission at acute phase exit, 73.3% (107/146) maintained their remitted status at endpoint of the continuation phase. Of those having a partial remission at acute phase exit, 52.9% (92/174) achieved full remission by end of continuation. A greater proportion of patients maintained a partial or full remission status on COMB (90%) compared to nefazodone (80%, p=0.011) or to CBASP (82%, p=0.042). These differences reflected greater symptom re-emergence in the partial remission groups on CBASP and nefazodone monotherapy compared to COMB. Continuation treatment assignment was not randomized or blinded. There was no placebo group. Most patients with chronic forms of MDD sustained their acute phase response and more than 50% of partial remitters achieved full remission while continuing treatment with nefazodone, CBASP, or COMB. COMB was associated with less symptom re-emergence during the continuation phase than either monotherapy, particularly for partial remitters.