BACKGROUND: Aflatoxin has a negative impact on the health of both humans and animals. One of the reasons for financial losses in the chicken sector is aflatoxicosis. In chickens, aflatoxicosis results in lowered growth rates and egg production, increased mortality, and diseases susceptibility. The current investigation sought to determine the mould's prevalence at the Giza and Assiut Governorates. Then, the isolated toxigenic strain was used to obtain aflatoxin B1, which used to evaluate the dietary influence of curcumin and nano curcumin on growth performance, carcass traits, biochemical, aflatoxin residue, and pathological lesion of liver, spleen, and intestine in Cobb broiler chickens. 120 hatched chicks were divided into 4 group. The groups were control fed basal diet without additives, Afl group fed diet contaminated with aflatoxin, Afl + Cu group fed diet contaminated with aflatoxin and curcumin as a feed additive (7 g curcumin/kg diet), and Afl + Nano-Cu group feed diet contaminated with aflatoxin and nano curcumin as a feed additive (400 mg nano curcumin/kg diet). RESULTS: The results indicated that curcumin better than nano curcumin in ameliorating the deleterious effects of aflatoxin that appeared in improving the body weight gain, liver function, and pathological condition of liver, spleen, and intestine than nano curcumin fed group. CONCLUSION: The current study offers an experimental scientific foundation for the use of curcumin as a medicinal medication or supplement in animal husbandry practices.