We examined the influence of acorn abundance on fall and winter diets and on nutritional and reproductive status of white-tailed deer (Odocoileus virginianus) in the Southern Appalachians from 1983 to 1988. When acorns were abundant, they dominated the diet; when they were scarce, leaves of broadleaf evergreen species, primarily rosebay rhododendron (Rhododendron maximum), largely replaced acorns in the diet. When acorn production was poor, kidney fat indices in winter were significantly lower for most sex and age classes. Also, reproductive rates of yearling does were significantly lower, and conception dates were significantly later when acorns were scarce. Reproductive rates of adults were not appreciably affected by acorn abundance. Because acorn abundance is largely independent of deer density, the important role of acorns in deer nutrition presents special problems in deer management.