Taiwanese mothers have identified insufficient sleep as a major manifestation of postpartum depression. Few studies have thoroughly examined the relationship between sleep and depression during the early postpartum period, however. The objectives of this study were to compare the characteristics of both the postpartum sleep and daytime sleepiness of depressed first-time mothers and of their non-depressed counterparts, and to determine the factors that significantly increased mothers' risks of being depressed. A non-probability sample of 163 first-time mothers completed a questionnaire between the 13th and 20th days of the postpartum period. The Center of Epidemiological Studies- Depression and Pittsburgh Sleep Quality Index were used to measure mothers' experiences of depression symptoms and sleep. Daytime sleepiness was estimated in four ways, derived from the Roy Adaptation Model. The results indicated that the depressed mothers had poorer sleep quality than the non-depressed mothers, slept less efficiently, reported more sleep disturbances, and exhibited more daytime dysfunctions. Mothers who frequently perceived their daytime sleepiness to be affected by infant-care performance were more likely to be depressed. The study' s findings support the view that there is a connection between depression and poor sleep among postpartum mothers in Taiwan, and indicate that depressed mothers' experiences of poor sleep are multi-faceted, and not simply a matter of insufficient sleep.