 The association between intravenous iron use and decrease in serum phosphorus and vitamin D levels, with increased fractional excretion of phosphorus, has been observed with older iron preparations, such as saccharated ferric oxide. However, hypophosphatemia and osteomalacia have been reported with iron carboxymaltose, a newer iron formulation. There is no information in the literature about phosphorus and vitamin D levels after treatment with venofer or ferrlecit. We intend to check phosphorus and vitamin D serum levels in our patients prior to and after treatment with these iron formulations. 