This experiment was conducted to determine the dietary supplementations of betaine on performance carcass, bone and blood traits of broilers in natural summer condition. A total of 180 broilers were divided into three experimental groups. The experimental diets were; Control, without any dietary addition, dietary supplemental betaine (Betafin (R)) 1 g kg(-1) and (3) 2 g kg(-1). The experimental diets were offered to respective broiler chicks for 6 weeks. Additional betaine decreased body weight at 6 weeks and body weight gain 3-6 and 0 to weeks (p<0.01). Feed intake and feed conversion ratio were not affected by treatments (p<0.05). Dietary betaine supplementation did not affect carcass weight and composition, breast and thigh meat pigmentation and pH value of thigh the broilers. Tibia width was decreased by 1 g kg(-1) betaine (p<0.05), but shank and tibia measurements were not affected by betaine. Serum alanin aminotransferase levels were reduced by both 1 and 2 g kg(-1) supplementation of betaine (p<0.05), but other blood constituents were not affected.