Factors that cause insulin resistance have always attracted the attention of scientists; the recent discovery of the interrelations between vitamin D and the cardiovascular system, immunomodulation, metabolic syndrome, autoimmunity and certain carcinomas has enhanced the popularity of vitamin D. Some studies detected that pancreatic β cells express a vitamin D receptor, and allelic variations in genes involved in vitamin D metabolism suggested a role for 25 (OH) vitamin D3 in the regulation of insulin secretion and glucose intolerance(11). The gene discussed is INS; the disease is metabolic syndrome.