Leukemic infiltration of the kidneys is a very rare cause of renal failure. A woman with acute lymphoblastic leukemia presented with nonliguric renal failure and was found to have massively enlarged kidneys. The size of the kidneys was dramatically reduced through the combined effects of local radiation therapy and systemic chemotherapy. Because this rapid shrinkage of the kidneys was associated with improvement in renal function, the uremia was ascribed to leukemic infiltration. As a consequence of rapid tumor lysis in the presence of renal failure, marked hyperphosphatemia and hypocalcemia developed. The literature experience with renal failure secondary to leukemic infiltration of the kidneys is reviewed.