The effects of chromium methionine supplementation on performance and serummetaboliteswere evaluated in broiler chickens.Two experiments were conducted at22 oC, thermoneutral, (TN) and33±2 oC, heat stressed (HS) conditions. Two hundred and eighty eight male broiler chicks (Ross 308) were allocated to four treatments in a completely randomized design. Treatments with 0 (control), 200, 400 or 800 ppb of chromium methionine for 42-d experimental period carried out. Serum metabolitesand performance were determined. Supplementing the diet of TN and HS conditions broilerswith chromium methionine improved feed intake (FI) and body weight (BW) (P<0.05), but Feed conversion ration (FCR) of broilers was not affected by different levels of supplemental chromium.Chromium methionine increased serum HDL contents, but decreased glucose, (GLU), cholesterol (CHL),triacylglycerol (TG) and LDL concentrations (P<0.05) in both TN and HS temperature. The results of these experiments indicated that supplementation of chromium methionine in the ration improved performance and influenced serum metabolites onthermoneutral andheat-stressed broiler. Manuscript profile