The histology of testis in albino rats submitted to hypoglycemic comas was studied. Comas were produced by either insulin or tolbutamide. No changes were seen in prepubertal animals, but in adults, injuries were seen in the seminiferous epithelium, coning of cellular and intercellular vacuoles, sloughing, nuclear pyknosis and multinucleated cells. Congestion and oedema were invariably present in the interstitium, though no injury was seen in any other testicular structure. Lesions increased in number and intensity with repetition of comas and recovery after comas was incomplete. Hypoglycemia is considered the specific cause of the injuries.