This study aimed to improve antivenom production using gamma radiation and calcium phosphate nanoparticles (CPN) as adjuvant. Toxicological and immunological properties of the Naja haje venom before and after exposure to radiation were estimated. The immune response of immunized rabbits was evaluated. Toxicity of irradiated venom was reduced six times as compared to native venom. Moreover, no change in antigenic reactivity between native and irradiated venoms. Serum titer produced with irradiated venom loaded on CPN showed highest titer and neutralization capacity as compared to other sera. Thus, irradiation and nanoparticles adjuvant could be a new approach for snake antivenom production.