The present study aimed to explain the role of acetylsalicylic acid (ASA) and sodium bicarbonate (SB) in alleviation of the negative effect of heat stress on growth performance, some serum biochemical changes and hematology of broiler chicken reared under heat-stress (33-35◦C). One hundred and twenty, 15-day-old apparently healthy broiler chickens were selected and randomly assigned into 4 groups fed on a basal diet without any supplement (control) or supplemented by 0.05% ASA, 0.5% SB or both 0.05% ASA and 0.5% SB respectively. The results explained that dietary supplementation of acetylsalicylic acid (ASA), sodium bicarbonate (SB) or combination of ASA and SB significantly (P˂0.05) increased final body weight and total gain of broiler chicks reared under heat stress by about (2.8% and 3.9%), (2.6% and 3.6%) and (8.8% and 6.8%) respectively, moreover, had no effect on total feed intake and non-significantly (P≥0.05) improved average FCR throughout whole experimental period by about 1.4%, 2.4% and 4. 2% respectively compared with control. All treatment reduced serum ALT, AST and alkaline phosphatase activities and serum total protein, albumin, sodium and chloride concentrations compared with control. Results concerning the effect of ASA, SB supplementation in broiler chicken ration reared under heat stress alone or combined together non significantly increased Hb%, RBCs counts, platelets count and WBCs count compared with control. Moreover, all treatments had no significant effect on basophils%, eosinophil% and monocytes%, while decreased heterophils% and increased lymophocytes% compared with control. It could be concluded that dietary inclusion of acetylsalicylic acid and sodium bicarbonate separately or in a combination in broiler ration can be used to alleviate the negative effect of heat stress in broiler chicken performance, liver heath and hematology during summer season in Egypt.