One hundred and twenty 1-d old commercial broiler chicks (Cobb) were divided in to four groups with six replicats, to investigate the effect of dietary supplementation with organic chromium (Cr), organic selenium (Se) and Vitamin E (Vit.E) on some physiological and immunological parameters. The first group was the control group, while the second group was fed the basal diet supplemented with organic chromium (0.8 mg/kg diet), the third group was fed the basal diet supplemented with organic selenium (0.3 mg/kg diet) and the fourth group was fed the basal diet supplemented with vitamin E (200 IU/kg diet). Temperature and humidity were recorded daily and the Temperature-Humidity Index (THI) was calculated, which demonstrated that birds were exposed to heat stress throughout the experiment period. The results showed that increasing dietary levels of organic chromium, organic selenium and Vitamin E especially Vitamin E supplementation could improve plasma total protein and globulin (p<0.05) values at 42 DOA. Supplements could significantly (p<0.05) enhance the total antibody titer against Newcastle disease Virus (NDV) either for the primary or secondary response and induce higher expression of heat shock protein 70 (HSP 70). Insulin-like Growth factor-I (IGF-I) level was improved significantly (p<0.05) due to increasing dietary organic chromium levels followed by vitamin E than organic selenium. It could be concluded that the dietary addition of organic chromium (Cr), organic selenium (Se) and Vitamin E (Vit.E) triggered improvements in the physiological and immunological measurements of broilers reared under heat stress conditions