The aim of this study was to explore the role of affect management in postpartum relapse to smoking. Between January and October 2005, 65 women who smoked prior to pregnancy but not during the last month of pregnancy were recruited from Brigham and Women's Hospital in Boston, MA, and followed for 24 weeks. Surveys administered at baseline, 2, 6, 12, and 24 weeks postpartum assessed smoking status and symptoms of depression (Beck Depression Inventory, BDI) and anxiety (Beck Anxiety Inventory, BAI). Qualitative interviews were conducted when women relapsed or achieved an elevated BDI or BAI score. Elevated BDI or BAI scores did not predict relapse, suggesting that symptoms that make women vulnerable to relapse may not be fully captured by these instruments. Women described feelings of anger or frustration as part of the relapse experience. Women with elevated BDI or BAI scores who did not relapse were more likely to normalize their mood symptoms as part of the postpartum experience and described more adaptive and active coping strategies. Interventions designed to prevent postpartum relapse to smoking may need to target a broader range of negative affect and mood management strategies to increase the likelihood of efficacy.