The present study aimed at: 1. Examination of commercial chicken and duck eggs for the possible presence of aflatoxins. 2. Study of the sex susceptibility of mature chickens when fed on ration containing aflatoxins. 3. Study of clinicopathological effects on their ovaries and testicles. In this investigation, 100 chicken and 50 duck eggs collected from markets in the vicinity of Assiut Governorate, were examined individually for the presence of aflatoxins in the whites and yolks. The study revealed that the examined eggs contained no aflatoxins. Experimentally, aflatoxin BV(8.1 ppm) and G. (1.6 ppm) were incorporated into the feed of five laying hens and five mature cooks for three weeks duration. The layers showed cessation of egg production during the whole feeding period. Histopathological examinations revealed that, the ovaries showed follicular atresia while testicles were normal. It was shown that, aflatoxicosis cause pathological changes in the chicken ovaries, which has a detrimental effect on egg production