Soy sauce has been traditionally used as both a condiment and health food with antioxidant, anti-mutagenic, and antitumor activities. The present work aims to study the effect of soya sauce supplementation on the testis of male rats. Twenty-four male albino rats were divided into 3 equal groups. Group I; control males, group II; received low doses for consecutive 30 days, and group III; received a high dose of soy sauce for consecutive 15 days then recovered for another 15 days. Soy sauce in low doses decreases the amount of total white blood cells, red blood cells, hemoglobin, lymphocytes, and platelets levels than high doses while increasing neutrophils, and monocytes in high doses of soya. Histopathological examination showed that the testis of the low dose group had marked irregularity of seminiferous tubules periphery and degeneration of Leydig cells. Spermatogenesis arrest at the spermatid stage and degenerated spermatozoa were noticed in the center of tubules. Also, a significant increase in collagen fiber content of the testis was found in comparison with controls. However, rats treated with high doses showed restoration of the normal testis architecture. Furthermore, free testosterone hormones, lipid peroxidation, and nitric oxide level were decreased in the low-dose group than in the high-dose group. In contrast, Glutathione level was increased in rats supplemented with a high dose than a low dose of soya sauce. Supplementation of rats with Soya sauce is impact testicular tissue in dose and duration time-dependent.