The problem of hyperphosphatemia in patients with chronic renal failure is reviewed. The importance of high plasma phosphorus levels in the pathogenesis of hyperparathyroidism is concisely discussed. Basic concepts about phosphorus metabolism in normal persons and in patients with chronic renal failure are outlined. This is followed by a detailed discussion of the various therapeutic methods to control hyperphosphatemia. Dietary restriction, dialysance of phosphorus, and the use of the currently available phosphorus binders are comprehensively discussed. Finally, the various clinical situations associated with failure to control hyperphosphatemia are reviewed.