The fisher (Pekania pennanti) is a forest-dwelling mesocarnivore native to northern North America. The species had been extirpated from many southern parts of its historic range, but several states have implemented fisher re-introduction programs over the past 40 y. While many studies have previously examined fisher diet, most occurred in northern and western portions of the species' range where mixed and coniferous forests are the dominate cover types. We examined fisher diet, in a re-introduced population in the central Appalachian Mountains where deciduous forests were the dominate cover type. We collected 91 fisher carcasses from 2002–2014 and examined their stomach contents. We detected mammalian and avian prey in 82.6% and 10.9% of stomachs, respectively. Fishers we sampled consumed a variety of plant materials (n = 11) and prey items (n = 30 spp.). Diet composition of males and females overlapped considerably (O = 0.87). Our most noteworthy and novel finding was the presence of fisher remains in 11 (12%) stomachs. We suggest here that rapid population growth of Pennsylvania fishers may have resulted in aggressive behaviors underlying our observations of interspecific consumption. Future research that examines the cause for intraspecific consumption in this central Appalachian fisher population would be a worthy endeavor.