Vitamin D is fat soluble vitamin produced in the skin by sunlight exposure. It is required for the maintenance of calcium and phosphorus homeostasis, skeletal growth and various other metabolic processes. The factors such as low sunlight exposure, age related decrease in cutaneous synthesis and low dietary intake contributes to the high prevalence of vitamin D inadequacy. It's deficiency is associated with various diseases like rickets in children and osteomalacia in adults. Low levels of vitamin D are also associated with increased risk of fractures, muscle pain and weakness, cardiovascular risk, diabetes mellitus, polycystic ovarian syndrome, infections and autoimmune disorders. The deficiency of vitamin D can be treated by adequate sunlight exposure, forticfiation of foods and supplementation of vitamin D.