Diabetes mellitus had a deleterious harmful effect on the testicular functionand the process of spermatogenesis and in turn the male fertility. The aim of thepresent work is to study the effect of induced diabetes mellitus on the testis andspermatogenesis in the adult albino rat and to evaluate the possible protective roleof the vitamin E. 140 adult male albino rats were used in the present study. Therats were divided into seven groups each consisted of 20 rats as follows: Group I(control group) : used as a control group , Group II : (Diabetes for one month)received a single dose of intra peritoneal injection of Alloxan monohydrate(150mg /kg body weight) for induction of diabetes and they were kept diabeticsfor one month , Group III : (Diabetes for three months) were rendered diabeticsand kept for three months then sacrificed, Group IV (Diabetes with vitamin Eadministration of a daily dose of 200 mg/kg of vitamin E orally for one month) ,Group V: (Diabetes with vitamin E administration for three months ) , Group VI :(Diabetes for one month then vitamin E administration for another one month) andGroup VII: (Diabetes for three months then vitamin E administration for anotherone month)