Lontra canadensis (River Otter) have been reintroduced throughout much of their former range in North America, but our understanding of the function they serve in ecosystems to which they have been reintroduced remains incomplete. We examined the winter diet of reintroduced River Otters in Kentucky based on contents of 126 stomachs collected over three trapping seasons, 2006–2009. Fish and crayfish were the main prey, occurring in 86% and 27% of stomachs containing prey items, respectively. We identified 8 families and 11 genera of fish and 4 genera and 6 species of crayfish in the diet of River Otters. The most frequently consumed family of fish by occurrence was Centrarchidae (36%), followed by Catostomidae (11%), Cyprinidae (11%), and Clupeidae (7%). Centrarchidae were also found at the greatest volume (53%) of any family of fish, followed by Catostomidae (14%), Clupeidae (12%), and Cyprinidae (12%). Of the centrarchids, Group A fish (Lepomis, Ambloplites, and Pomoxis spp.; 28%) occurred at a higher percent in the diet of River Otters than Group B fish (Micropterus spp.; 5%). River Otter diets did not vary between males (n = 68) and females (n = 58), adults (n = 46) and juveniles (n = 80), or those from the western (n = 64) and eastern (n = 62) regions of the state.