A feeding trial was conducted using twenty Ossimi lambs. Animals were divided into two equal groups (26.05±0.008 Kg). The objectives of the study were to compare the efficiency of animal performance during summer season using two types of concentrate feed mixtures (CFM) containing yellow corn grains (CFM1) or barley grains (CFM2) along with berseem hay.  Digestibilities of DM, OM, CP, EE, NFE and energy and serum total protein, albumin and globulin were better for lambs fed CFM1 than those fed CFM2. No differences were detected between CFM1 and CFM2 in respect with average daily gain and feed conversion. Feed cost/Kg live body weight gain  was lower for barley included ration than that included yellow corn. It   is concluded that barley grains could replace corn grains in manufacturing concentrate feed mixtures to decrease the cost of production of one kilogram of growth without any adverse effect on the productivity of lambs.