Diet of the bobcat (Lynx rufus) in the mid-Atlantic region of the United States is poorly known. Age, sex and time of year are thought to influence bobcat prey selection, but accounts vary. We examined the contents of 85 bobcat stomachs taken from Pennsylvania during autumn and winter 2000–2002. White-tailed deer (Odocoileus virginianus) and rabbits (Sylvilagus sp.) occurred most frequently as prey. A larger percentage of female bobcats consumed lagomorphs (28%) than did males (12%; P = 0.04). More male bobcats consumed meso-mammals (14%), including raccoons and porcupines, than did females (2%; P = 0.04). Diet did not differ between bobcats <2 y and bobcats ≥2 y. Variety of prey eaten was larger in autumn than in winter. Sexual differences in diet may be related to sexual dimorphism in this species and may help to effect interspecific niche partitioning. Winter weather reduces the availability of certain prey items in this region and may decrease the bobcat's ability to travel and hunt effectively.