Abstract: The study aimed to determine the effects of in ovo injection of nanocurcumin and vitamin E on the immunity and growth performance of broilers. Six hundred eggs containing live 17.5 day-old embryos were assigned to six treatments. Four groups were inoculated as follows: 0.05 mL corn oil containing 0.015, 0.030 mL/egg nanocurcumin, 0.037 and 0.074 IU/egg vitamin E, whereas two groups remained as un-injected controls and oil-injected sham. The chicks were reared under heat stress. The cellular immunity was significantly increased (p<0.05) by in ovo administration of vitamin E 0.037 and decreased by in ovo injection of vitamin E 0.074 at 8 and 12 h after injection as compared to control. Body weight gain 1-10 day was significantly decreased (p<0.01) by in ovo injection of nanocurcumin 0.015 and vitamin E 0.074, however, it and feed intake 25-42 day was significantly increased (p<0.05) by in ovo injection of nanocurcumin 0.030 without affecting feed conversion ratio. This study evidenced the in ovo administration of nanocurcumin 0.030 improved growth performance during 1-42 days, however, decreased the hatchability. Solutions did not have a significant effect on humoral immunity but cellular immunity was improved by in ovo injection of vitamin E 0.037.