Chemical analyses and in vitro digestibility data were obtained for forages used by mule deer (Odocoileus hemionus) during summer when deer occupy ponderosa pine (Pinus ponderosa) types. Dietary protein and phosphorus content diminished from 25 and 0.48 percent in May to 10 and 0.19 percent, respectively, in late summer. Dry matter digestibility declined from about 68 percent in May to 46 percent in August. Nutrient analyses of composite samples that simulated diet composition were fast and inexpensive, and provided results generally in agreement with values from weighted means of individual forages. The latter procedure is indicated, however, when more intensive data on forage quality are needed for management purposes.