Wilms' tumor in an adult is extremely rare, with less than 250 cases reported in the world literature. Treatment guidelines for pediatric Wilms' tumor are well established; those for adults are not. This article presents the case of a 19-year-old male diagnosed with Wilms' tumor after complaints of hematuria. He was categorized as Stage IV after nephrectomy and received post-operative radiotherapy and chemotherapy consisting of Vincristine, Adriamycin, and Actinomycin-D. Two years later he was found to have metastases to brain and lungs. He was treated with radiotherapy and bone marrow transplantation, and died of septic shock. The literature regarding Wilms' tumor in adults is reviewed, and current therapy is discussed.