Medicare costs for phosphate binders for US dialysis patients and patients with chronic kidney disease enrolled in Medicare Part D exceeded $1.5 billion in 2015. Previous data have shown that Part D costs for mineral and bone disorder medications increased faster than costs for all Part D medications for dialysis patients. Despite extensive use of phosphate binders and escalating costs, conclusive evidence is lacking that they improve important clinical end points in dialysis patients or non–dialysis-dependent patients with chronic kidney disease.