Occurrence of embryonal kidney tumors in patients with primitive neuroectodermal tumors, so-called central nervous system-renal neoplasia has been reported. An infant who presented with masses in the right lateral ventricle and the cerebellar vermis is reported. Histological examination showed primitive neuroectodermal tumors. Further investigation revealed tumors in the bilateral kidneys, which were removed subtotally and pathologically shown to be Wilms' tumors. The patient was then treated with anticancer drugs and irradiation. However, he developed lung metastases from the renal tumors and expired. At autopsy, a small tumor was found in the inferior horn of the left lateral ventricle. Histological finding showed a primitive neuroectodermal tumor. Also, bilateral large masses of recurrent Wilms' tumors, multiple metastases to the lungs and peritoneal dissemination were found. There is no evidence that this association is based on the selective neoplastic transformation of embryonal cells of similar histogenetic or cytogenetic origin. Several reports demonstrate the presence of embryonal cells in the nervous tissue which could imply a neuroepithelial origin for Wilms' tumors.