Postpartum depression is a significant public health problem affecting almost 600,000 US women every year. It may arise de novo in the postpartum period or continue from pregnancy. A number of evidence-based psychotherapies and medical treatments exist for major depression and postpartum depression. The obstetrical team has many opportunities to identify high risk and depressed women and refer them to mental health professionals or begin treatment with antidepressant medication. Careful assessment of risk factors for postpartum depression during pregnancy and monitoring depressive symptoms during pregnancy and the postpartum period will lead to better outcomes for women and their families.