This study was accomplished to designed to assess the appropriate concentrate: roughage ratio (C:R) ratio for better nutrient digestibility, rumen fermentation patterns, healthy and economic beef production in Egyptian buffalo calves. Sixteen buffalo calves aged about 18-20 months of 292.5±4.7 kg average body weight were randomly assigned into four groups of 4 animals each. The treatment diets were composed of four concentrate: roughage (C:R) ratios (80:20, A; 75:25, B; 60:40, C; and 55:45, D). The results revealed that increasing in the proportion of concentrate in the diet significantly (p <0.05) increased the digestibility of dry matter (DM), organic matter (OM), crude protein (CP), crude fiber (CF), ether extract (EE), nitrogen free extract (NFE) and the total digestible nutrients (TDN). Ruminal concentration of both volatile fatty acids (VFA) and ammonia nitrogen were increased linearly with increasing the dietary concentrate portion (60, 75 and 80), however the rumen pH were decreased (P<0.01) with increasing the concentrate level in the diet. In addition, increasing the concentrate proportion increased the dry matter intake of feed, average daily gain, final body weight; and feed cost per kg body weight.  Serum, glucose, and acute phase protein were increased by increasing the dietary concentrate portion. Feeding diet containing 60% concentrate showed better performance and economic efficiency per kg body weight gain when comparing with diet containing 75 % and 80 % concentrates levels. This study suggested that the diet consisting of 60: 40 concentrate: roughage ratio could be considered as the optimum diet for growing buffalo calves for better performance, efficient feed utilization, economic feed efficiency and low risk of sub-acute ruminal acidosis.