We describe the results of an open-label study designed to assess the effectiveness and tolerability of aripiprazole addition to an antidepressant in patients with major depressive disorder with postpartum onset who had not experienced significant clinical improvement following an adequate trial of an antidepressant. Eight of ten women completed the trial with augmentation of aripiprazole (2-10 mg) to their existing antidepressant treatment. Our results suggest a possible therapeutic role for aripiprazole when added to an antidepressant in non-breastfeeding women with postpartum depression. Aripiprazole addition appeared effective and safe with no serious adverse events reported.