Abstract: Aspergillus flavus and Aspergillus parasiticus are two important molds that produce Aflatoxin(AF). Humans and animals can be exposed to aflatoxins by consuming foods contaminated with the products of these fungi. Aflatoxin B1 (AFB1) is one of the most common mycotoxins found in human foods. In general, acute toxicity by is AFB1 less likely to occur than chronic toxicity. The principal target organ for aflatoxins is liver which may lead to hepatocytes and necrosis and also can be carcinogenic and cause immunosuppression. AFB1 could be toxic to the male reproductive system in man as well as wild and domestic animals. According to this study the AFB1 effect on testis and sperm of male rats which revealed pathological changes in testis and epididymis, with the high dosage of AFB1 the edematous fluid inside the tumbles increases while there are significant (p>0.05) decreases in the number of leydig cells, the height of seminiferous, as well as there was a significant decreasing in the number of spermatogenesis, spermatocytes and spermatids.