The effects of removal of all renal tissue on hematopoiesis, osteodystrophy, blood pressure regulation and metabolic functions are reviewed; and, the indications for, and results of, bilateral nephrectomy are discussed. Nephrectomy results in a more severe anemia in dialysis patients which is poorly responsive to androgen therapy. No differences were detected in the severity of osteodystrophy between nephric and anephric patients. However, bilateral nephrectomy can occasionally result in the acute onset of hypocalcemia. Blood pressure regulation must be accomplished in the absence of a functioning renin-angiotensin system. This is largely on the basis of volume, but changes in vascular tone may also be significant. Little is known about the metabolic consequences of nephrectomies. The effect on substances metabolized by the kidney is an area for further investigation. Kidney tissue should be preserved, if at all possible, and nephrectomy performed only for specific indications.