The Abstract: Diabetes Mellitus (DM) is a major health concern all over the world. The number of affected people is increasing every year. Many factors contribute to the disease including diet, genetics, lifestyle and so forth. The disease is characterized by hyperglycemia because of insuffiency of the insulin producing beta cells of the pancreas. There is need for alternatives to the conventional antidiabetic drugs to overcome their shortages vitamin D and calcium intake are thought to protect against DM our research aims to evaluate the effect of administration vitamin D, calcium and combination of both on glucose and insulin levels in diabetic rats. Diabetes mellitus was induced intraperitoneally in male Wister albino rats by injection of alloxan (150 mgkgG1 bw). Animals were divided into seven groups of eight rats each: group I served as normal control, group II act as diabetic control. The diabetic rats treated groups (III, IV, V, VI and VII) were treated, respectively with metformin at dose of 100 mgkgG1, vitamin D3 at dose of 12.5 μgkgG1, calcium gluconate at dose of 100 mgkgG1 both vitamin D3 and calcium gluconate and olive oil at dose of 0.3 mLkgG1 (serve as vehicle group). The treatments were performed by oral administration once a day for 28 consecutive days. The results showed that vitamin D3 and vitamin D3-calcium combination lowers blood glucose level and calcium alone was not statistically significant decreased glucose level. Supplementation with vitamin D3 with or without calcium increases insulin slightly when compared with normal control. (Am J Transl Med 2019. 3:104-111).