Sleep disruption and insomnia are common features of the postpartum period and may predispose women to develop affective illness. The aim of this study was to explore sleep and mood during the postpartum period in women at risk forpostpartum depression. Thirteen postpartum women participated in focus groups designed to elicit information about sources of sleep disruption, how sleep changes impacted their mood, and their preferences for insomnia treatments. Transcripts from the focus groups were analyzed using a grounded theory framework. Major themes included: mental arousal and breastfeeding are major sources of sleep disruption; women are ambivalent about accessing nighttime support; it is difficult for women to prioritize sleep; poor sleep leads to mood dysregulation; and women prefer nonpharmacological treatments for insomnia. Understanding sleep from the perspective of postpartum women can help inform treatments for insomnia in this population.