Cystic nephroma (CN) and pleuropulmonary blastoma (PPB) are rare tumors. In the cases presented here, a 13-month-old boy underwent right radical nephrectomy for CN. From the family history we learned that four years ago the patient's older sister underwent left radical nephrectomy for CN at a different center when she was 4 years old. A lung tumor was detected in the sister one year after nephrectomy. Biopsy from the lung tumor revealed PPB, and the sister died within one year after biopsy. To the knowledge of the authors, these cases represent the second reported familial occurrence of CN and the fourth of CN and PPB.