Year-round foraging of white-tailed deer (Odocoileus virginianus) on the na- tional forests of the Southern Appalachian mountains in Georgia, North Carolina and Ten- nessee was determined by analysis of rumen samples from 581 deer taken over 5 years and by sampling forage availability and evidence of browsing in selected habitat types. Spring and summer diets consisted mainly of green leaves and succulent twig tips of deciduous woody plants (58% in spring, 54% in summer). These forages were more abundant and used more intensively by deer in and around clearcuts than in adjacent older forests. Most other im- portant foods in these seasons (i.e., fruits, forbs and fungi) also were much more abundant in the clearcuts. Flowers of yellow-poplar (Liriodendron tulipifera), which dominated the diet in late May and earlyJune, and squawroot (Conopholis americana), a parasitic herb associated with red oaks ( Quercus spp.) and an important secondary food throughout most of the spring and summer, were more available in older forests. Fall and winter diets were influenced greatly by the availability of mast, especially acorns. When mast was abundant, it dominated the diet. When mast was scarce, deer fed mainly on the leaves of broadleaf evergreen woody plants, especially rosebay rhododendron (Rhododendron maximum). Twig ends were used little by deer during fall and winter. Older forests generally provided best foraging conditions for deer in fall and winter, being the primary source of mast and also producing about the same quantity of broadleaf evergreen foliage as clearcuts. Clearcuts and older forests provide complementary benefits to deer. Forests of intermediate age (after crown closure reduces browse availability and before onset of significant mast production) contribute much less to the deer forage resource than either clearcuts or older forests. Specific contributions of different forest age classes to the forage base vary with site characteristics. Implications of changing forest management policy are discussed.