Postpartum depression (PPD) is a common and serious mental health problem that is associated with maternal suffering and numerous negative consequences for offspring. The first six months after delivery may represent a high-risk time for depression. Estimates of prevalence range from 13% to 19%. Risk factors mirror those typically found with major depression, with the exception of postpartum-specific factors such as sensitivity to hormone changes. Controlled trials of psychological interventions have validated a variety of individual and group interventions. Medication often leads to depression improvement, but in controlled trials there are often no significant differences in outcomes between patients in the medication condition and those in placebo or active control conditions. Reviews converge on recommendations for particular antidepressant medications for use while breastfeeding. Prevention of PPD appears to be feasible and effective. Finally, there is a growing movement to integrate mental health screening into routine primary care for pregnant and postpartum women and to follow up this screening with treatment or referral and with follow-up care. Research and clinical recommendations are made throughout this review.