Preoperative transcatheter embolization of a renal neoplasm is helpful to the urologist, especially with large, hypervascular tumors. When combined with nephrectomy and hormonal therapy, it offers promise in the management of patients with renal carcinoma. Delay between embolization and nephrectomy seems to be important, but the optimal time for stimulating a therapeutic response has not been established. Among 49 patients in this series with known metastases, occlusion of the renal artery followed 4 to 7 days later by nephrectomy and hormonal therapy changed the course of the disease, producing a 36% response rate.