Acute renal failure proved fatal in a patient with metastatic breast adenocarcinoma, complicated by the hemolytic-uremic syndrome. Low-grade hemolysis probably was ongoing prior to a third course of chemotherapy that included mitomycin. Terminal renal failure was caused by glomerular infarction and tubular necrosis. Schiztocytes in the blood smear and casts in the urine sediment may be relative contraindications to prolongation of tumor-lysis therapy. Recent advances in "rescue therapy" for hemolytic-uremic syndromes justify dialysis at least on a temporary basis.