Aloe vera has many applications in traditional medicine .In present study, the hypoglycemic effects of the Aloe vera and its protective effects on the adrenal gland on diabetic rats were studied. 50 mature male rats (2-3 months old) and weighing 200-250 were divided randomly into 5 groups (10 rats in each groups) as following: Group I (control), has not received any treatment. Group II (Diabetic) which received 65 mg/kg Streptozotocin (IP). and rats with blood glucose more than 250 mg/dL were considered as diabetic. Group III, diabetic rats which received the Aloe vera gel with dose of 400 mg/kg daily. Group IV, diabetic rats which received insulin in 10 units/rat. Group V,received Aloe vera gel only. On days 15 and 30 of experiment, blood glucose of all groups were measured. Animals were euthanized with ether. Then, tissues samples were collected from adrenal glands, and fixed in 10% neutral buffered formalin solution. The sections were made using routine paraffin embedding method and stained by haematoxylin-eosin (H & E). Histomorphometrical parameters were evaluated using Digital Dino-Lite lens and Dino capture software 1. The results showed that thickness of fasciculata layer and the size of the spongiocyte were increased significantly in diabetic rat (P≤0. 05) but the thickness of fasciculata layer was decreased significantly in diabetic rats which received Aloe vera and insulin (P≤0. 05). The blood glucose was decreased significantly in diabetic rats. Conclusion, Aloe vera can be has beneficial and protective effects on adrenal glands in diabetic rats.