Diffuse bilateral infiltration of the kidneys by lymphoma cells is a rare but well-documented cause of acute renal failure (ARF). Only 51 such cases have been reported, 15 of which had ARF as the initial presentation of lymphoma. The clinical and pathologic features of these 15 cases and of two additional cases reported herein are reviewed. The diagnosis should be suspected in a patient with ARF, bilateral enlargement of the kidneys, minimal proteinuria, nonspecific findings on urinalysis, and absence of features of allergic tubulointerstitial nephritis. Renal imaging techniques may suggest the possibility of lymphomatous infiltration, but only renal biopsy or autopsy can provide a definitive diagnosis. Although modern chemotherapy and/or radiation therapy usually leads to a dramatic normalization of renal function, almost all patients eventually die of widespread recurrent lymphoma, despite the absence of clinical or pathologic involvement of the kidneys at the time of death.