This experiment was conducted to study the effect of chromium supplementation on performance and blood serum biochemistry of lactating buffaloes.  Therefore, thirty lactating buffaloes (aged 3-6 years, average body weight 567± 22.78 kg) were equally divided into two groups. Group one (G1), control, which received no chromium supplementation and group two, treated group (G2), received 5mg/day chromium methionine from 6 wk to 18 wk postpartum. Milk production and milk composition were evaluated by weekly. Serum biochemistry concentrations (serum glucose, cholesterol, triglyceride, total protein, cortisol and insulin concentration) were estimated on the 42^th, 72^th, 102^th and 132^thday. The obtained results indicated that milk production was significantly affected by chromium methionine supplementation during the entire period (P<0.05) but no significant effect on milk composition. Supplemental chromium had no significant effect on serum glucose, cholesterol, triglycerides and insulin concentration. However, chromium supplementation tended to increase significantly serum total protein level and decrease cortisol level(P<0.05). The results of this study showed that dietary chromium methionine supplementation increased milk yield and total protein concentration in the blood.