Postpartum depression occurs in about 10% to 20% of childbearing women. When developing a treatment plan, clinicians need to balance the risks of untreated maternal depression, the benefits of breastfeeding, and the risks associated with infant exposure to medication in breast milk. Data on the short-term safety and long-term consequences of antidepressant use during breastfeeding are meager, but several commonly used antidepressants appear to transfer at low levels into breast milk and may or may not be detectable in infant serum. Few adverse events have been reported, and medication discontinuation has been associated with a reversal of those events. Therapeutic doses should be as low as possible, and infants (especially newborns) should be closely monitored for adverse events. Nonpharmacologic treatments should also be considered.