A trial was carried out to determine the effects of diet supplementation with propolis on performance and activity of antioxidant enzymes in broiler chickens. Two hundred and forty one-day-old unsexed Cobb broilers chicks were randomly distributed into four equal experimental groups; with three replicates of 20 chicks each. Chicks were fed different levels of propolis including 0, 125, 250, and 500 mg/kg diet for 6 weeks. The mean weight gain, feed consumption and feed conversion ratio were recorded weekly. Carcass traits and hematological parameters were determined at the end of the experiment. Also, plasma malondialdehyde (MDA) level, superoxide dismutase (SOD), glutathione peroxidase (GSH) and catalase (CAT) activities were determined. The results showed that, Using of propolis at 125 mg/kg in the diet lead to significant increase (P<0.001) in body weight (2866.67g); final weight gain (2825.67g) and improve feed conversion ratio (1.62). Relative organs weight, dressing and carcass percentage were improved in the supplementation groups. In addition, propolis supplementation showed significant improvement in the WBCs, RBCs, Hb, PCV and MCHC. Also, the results showed that the administration of propolis causes significant (P<0.01) decrease of malondialdehyde (MDA) level and significant (P<0.001) increase of antioxidant system as superoxide dismutase (SOD) activity, CAT and glutathione peroxidase (GSH) levels in blood. Supplementation of natural antioxidant (propolis) facilitates reduction of the negative effects on performance and enhanced the antioxidant system which resulted in decreased mortality as compared to the control. Economic efficiency of groups fed supplemented diet with propolis had improved significantly compared to control.