A 61-year-old woman underwent a left radical nephrectomy for Stage II anaplastic Wilms' tumor. She received no adjuvant therapy. One year later computerized tomography (CT) of the abdomen revealed a mass in the left renal fossa and retroperitoneal adenopathy. A CT-guided needle biopsy was nondiagnostic. The patient had progressive disease after treatment with dactinomycin, doxorubicin, and vincristine, but achieved a complete response after treatment with cisplatin and etoposide. The therapy of Wilms' tumor in adults is discussed.