This study was conducted to evaluate the effect of chromium methionine on some productive performances and physiological responses of growing Barki lambs. Thirty-three lambs averaged 35.37 kg body weight; 5 months old were divided into 3 similar groups of 11 animals according to their live weight. The three groups were assigned at random to the three experimental groups as follow: G1: control ration without chromium, G2: control ration with 1.50 mg chromium/head/day, G3: control ration with 3 mg chromium/head/day. The growth trial was conducted for 90 days. Lambs were weighed every two weeks before morning feeding after 15 h of fasting. Body weight gain was recorded and daily feed intake was calculated. Dry matter (DM), total digestible nutrients (TDN) and digestible crude protein (DCP) intake were calculated. Feed efficiency ratio was calculated. Results indicated that, either G2:  1.50 mg /head/day or  G3:  3 mg /head/day  Cr supplementation had no effects on the digestibility of  DM, OM, CP , EE and DCP, but G3 (3 mg /head/day). But had significant (P<0.05) increase on digestibility of CF, NFE and TDN compared with G2 and control group. At the same time Cr supplementation did not affect onglobulin, creatinine, ALT and AST in blood plasma. Furthermore, no effect on urea. At the same time G3 (3 mg /head/day) Cr supplementation led to increase protein, albumin and blood glucose compared with G2 and control group. In addition, Cr supplementation had no effects on rumen pH, Total volatile fatty acids (TVFA^'s)   and ammonia concentrations at zero time and at 4 hours post feeding. At the same time G2 (1.50 mg /head/day) or G3 (3 mg Cr/head/day) had significant (P<0.05) increase total weight gain and average daily gain. Thus, Cr supplementation in G2 and G3 improved feed efficiency. From the present results it can be concluded that supplementation of Cr in organic form led to positive effect on deferent performances as a result of improving physiological responses.