<p>Diabetes mellitus causes biochemical abnormalities affecting different system. It is found that diabetes mellitus also affects male reproductive system causing infertility in men. The morphological study of the testis in diabetic condition was done as it represents the primary organ of male reproductive system. A total of twelve adult male Wistar rats were used in this study. The rats were divided into two groups, control and diabetic group. One group of rats was made diabetes by intraperitoneal injection of streptozotocin (STZ) whereas the other group remains as control. After six months, the testis was removed from the scrotum of both the groups, to study the morphological changes in the testis. It was found that hyperglycemia significantly alters the morphology of the testis of diabetic rats.</p>