Intake and apparent digestibility of nutrients, ruminal ammonia concentration, ruminal pH, and microbial protein synthesis were evaluated in sheep fed diets containing Stylosanthes cv. Campo Grande silage (StS) or corn silage (CS) with and without concentrate [C; 40% of the dry matter (DM)]. Four sheep with an average initial body weight of 41 ± 2.68 kg were used and were distributed in a 4 × 4 Latin square design, arranged in a 2 × 2 factorial scheme. The StS diets with C showed similar intake of DM and total digestible nutrients (TDN) (P > 0.05) in comparison with CS diet with C. However, in the diets without C, StS showed lower intake of TDN than CS (P < 0.05). The digestibility of organic matter (OM) did not differ between the StS and CS in the diets with C (P > 0.05). The efficiency of microbial protein synthesis was also similar (P > 0.05) between the StS and CS diets with C (59.13 and 66.11 g CP/kg TDN, respectively). The Stylosanthes cv. Campo Grande silage is a suitable roughage source to feed sheep, in diets containing 40% concentrate in the total DM.