Ideal pasture systems must supply high yields of quality forage throughout the grazing season. When cool‐season grasses predominate, forage is often in short supply during the summer months. This study was designed to compare improved cultivars of perennial, warm‐season grasses that were grown for pasturage in July and August. Pure stands of ‘Pawnee’ big bluestem (Andropogon gerardi Vitman), ‘Holt’ indiangrass (Sorghastrum nutans (L.) Nash), ‘Pierre’ sideoats grama (Bouteloua curtipendula (Michx.) Torr.), and ‘Nebraska 28’ and ‘Summer’ switchgrass (Panicum virgatum L.) were grazed with yearling steers from 1973 to 1975 at the Pasture Research Center, Norbeck, South Dakota. Grazing was initiated about 9 July and continued for 42 days on big bluestem, 38 days on sideoats grama, 33 days on Nebraska 28 switchgrass, and 31 days on indiangrass and Summer switchgrass. Steer gains averaged 1.08 to 0.70 kg/day, and were highest on indiangrass, similar on Nebraska 28 and Summer switchgrass and sideoats grama, and lowest on big bluestem. Number of steerdays of grazing per hectare ranged from 199 on big bluestem to 111 on indiangrass. Beef gains per hectare ranged from 147 to 112 kg, and were highest and similar on Nebraska 28 and Summer switchgrass and big bluestem, and lowest on indiangrass and sideoats grama. The results of this experiment indicate that big bluestem and switchgrass pastures can be used successfully for beef production in July and August.