Controversy exists in reference vitamin D values and testing methods to assess vitamin D status. Vitamin D testing would be justified in institutionalized older adults, in subjects with parathyroid disease, phosphocalcium metabolism alterations and malabsorption syndromes. In general, vitamin D supplementation would be indicated in patients with chronic kidney disease with severe hyperparathyroidism, hypoparathyroidism, malabsorption, and in case of confirmed vitamin D deficiency in institutionalized older adults and in people with existing phosphocalcium metabolism alterations. It is recommended to avoid vitamin D supplementation in pregnant or lactating women, unless the benefits outweigh the harms. Exogenous vitamin D does not reduce mortality, cardiovascular events, metabolic diseases or cáncer.