Despite the high prevalence of postpartum depressive disorders, many signs and symptoms of this illness are dismissed as normal physiologic changes associated with childbirth. Prompt recognition and treatment are imperative in order to limit the negative impact on both the mother and infant. Mood disturbances may have a minor functional impact that respond well to social support (eg. postpartum blues) or cause significant functional compromise requiring more aggressive therapy (eg. postpartum depression). The most extreme case of postpartum depressive disorder, postpartum psychosis, occurs when patients develop psychosis, mania, or thoughts of infanticide. Depression during pregnancy or the presence of risk factors suggests the need for careful follow-up. If postpartum depression develops, psychotherapy is the first-line treatment. Antidepressant treatment may be warranted for some patients, and the risks and benefits to both the mother and infant should be considered in the decision to institute pharmacotherapy.