Background: Vitamin D deficiency is one of the prominent nutritional deficiencies in India that needs special attention. The effects of hypovitaminosis D on skeletal and cardiovascular functions are well known. However, its effect on metabolic disorders like type 2 diabetes mellitus (T2DM) is still left unexplored. Aim and objectives: our primary aim is to find out the potential effect of deficiency of vitamin D in T2DM patients. Material and methods: The study was conducted on 250 T2DM patients mainly from Madhya Pradesh, India. Among them, 125 had hypovitaminosis D (case group) and were compared against the control group of 125 patients with normal serum vitamin D. Result and Conclusion: The present study reveals the potential effect of hypovitaminosis D on T2DM comorbidities where the complications are exacerbated during deficiency or insufficient of vitamin 25(OH)D3. Major organ functions including cardiac, hepatic, and renal functions are affected significantly. T2DM patients who are deficient in vitamin 25(OH)D3 are more prone to recurrent infections. The results suggest the importance of keeping a normal level of vitamin D in diabetic patients to avoid or reduce potential comorbidities