Quality and quantity of feed are the major factors in increasing ruminant productivity under tropical conditions. Increase in energy density in diets by providing larger quantities of concentrate feeds may improve feed efficiency and animal performance contributing to higher overall efficiency of utilization of dietary energy for body weight gain. Therefore, the objectives were to determine the effects increasing levels of concentrate on performance, intake and digestibility of lambs. Fifteen crossbred lambs (initial BW of 18.2 ± 3.2 kg and 100 d old) were used in a randomized complete block design according to initial BW and age. Lambs were penned individually during 45 d and fed an isonitrogenous (16.6 ± 0.55 CP, DM basis) diet. Increasing levels of concentrate were 40, 60, or 80% corresponding to the experimental diets C40, C60 and C80, respectively. Data were analyzed using SAS PROC Mixed procedure and means compared by Tukey Test. Effects were declared significant at P ≤ 0.05. No effect were observed on Dry matter (DM) intake (0.76, 0.87 and 0.85 kg/d for C40, C60 and C80) and crude protein (CP) intake (0.14, 0.16 and 0.15 kg/d or C40, C60 and C80). The DM digestibility was greater (P ≤ 0.01) for lambs fed C60 and C80 diets (80.18, 87.53 and 88.16% for C40, C60 and C80, respectively), while CP digestibility was unaffected (P ≥ 0.05) by concentrate levels (91.03, 92.21 and 91.56% for C40, C60 and C80, respectively). The Neutral Detergent Fiber (NDF) intake decreased for lambs fed C80 diet (P ≤ 0.05) while NDF digestibility was unaffected (P ≥ 0.05). ADG and G:F were greater (P ≤ 0.01) with increasing concentrate levels. Average daily gain was 60.1, 126.1 and 232.6 g/d while G:F was 0.08, 0.14 and 0.23 for C40, C60 and C80, respectively. It is concluded that supplementation of concentrate between 60 to 80% improves DM digestibility and performance of crossbred lambs without affect DM intake.