Free 25OH Vitamin D has received increasing attention over the last four years. More and more studies support the importance of free 25OH Vitamin D, suggesting that this fraction of 25OH Vitamin D is a better measurement of Vitamin D status rather than the total 25OH Vitamin D in pregnancy, renal disease, liver disease and intensive care units. This presentation will review recent evidence-based studies in the areas of supplementation strategy with Vitamin D2 / D3, evaluation of Vitamin D status during pregnancy, respiratory diseases, and monitoring of chronic kidney disease (CKD) patients.