Diabetes mellitus (DM) is a group of metabolic diseases characterized by chronic hyperglycemia resulting from defects in insulin secretion, insulin action, or both. Vitamin D deficiency continues to be a public health problem in many countries despite the availability of cheap and effective means to prevent this disease, Vitamin D deficiency in now considered pandemic. The actions of vitamin D are not limited to skeletal health benefits and may extend to preservation of insulin secretion and insulin sensitivity. Pancreatic insulin secretion is selectively inhibited by hypovitaminosis D. Several reports have demonstrated an active role for vitamin D and especially its bioactive form, 1,25(OH)2D3, in the regulation of endocrine pancreas function, especially the beta cell. An important role for vitamin D is suggested by the presence of the VDR in pancreatic beta cells.