The current study aimed to investigate the impacts of different gradual levels of rice bran oil (RBO) on the growth rate, carcass traits and blood parameters of broilers. A total of 160 unsexed chicks seven-days old were randomly divided into four treatment groups. The treatments were 0 (control), 0.4, 0.8 and 1.2% rice bran oil. The results showed that rice bran oil had significant effects on live body weight (LBW) and body weight gain (BWG) at all studied ages. Apart from feed intake (FI) at 1-5 wks of age, significant (p <0.05) impacts were observed in FI due to RBO. Use of RBO in the diet did not affect feed conversion ratio (FCR) of chicks at all ages. All carcass traits including carcass, dressing and giblets yields were statistically (p < 0.05) affected by RBO. Apart from total protein and globulin, RBO did not affect (P>0.05) all liver and kidney functions. It could be concluded that use of RBO at 0.8 g/kg diet caused some deleterious effects on the performance and carcass traits; but the use of RBO at all different levels in broiler diets did not affect most of blood parameters.