From 1961 to 1977, thoracotomy was performed on 19 patients with pulmonary metastasis of choriocarcinoma in Nagoya University with regard to the role of thoracotomy in management of pulmonary metastasis of choriocarcinoma. Our surgical indications for the disease are: 1) the patients must be a good risk for surgical intervention. 2) The primary malignancy be controlled. 3) Evidence of pulmonary metastasis be limited to the lung. 4) The urinary human chorionic gonadotropin (hCG) titers should be controlled at low levels below 1000 mIU/ml by preoperative chemotherapy. At levels below 200 mIU/ml, the indication for surgery will be assessed by the cellular response to chemotherapeutic agents. As an operative procedure, in view of a low incidence of lymph nodes metastases, extended pulmonary surgery appears to be unnecessary providing that the gross pulmonary lesion is removed by partial resection of the lung or lobectomy. Postoperative adjuvant chemotherapy is required to induce a complete remission of the choriocarcinoma.