Isolated lung metastasis occurs in about 1% of all colorectal cancer cases. As in the case of isolated liver metastasis, resection of isolated lung metastasis results in 5 year survival rate of about 30%. PURPOSE: This study was performed to evaluate the survival benefit after pulmonary resection for metastatic colorectal cancer. METHODS: Between January, 1992 and March, 1998, twelve patients underwent lung metastatectomy from colorectal cancer at the Seoul National University Hospital. We evaluated the clinical characteristics of patients and analyzed the follow-up results in 10 patients whose medical records were available. Indications for resection of pulmonary metastasis were complete resection of the primary tumor, no other organ involvement except lung, completely resectable lung lesion, and tolerable general condition of patient for lung resection. RESULTS: Two patients had their primary tumors located in colon and 8 in rectum. Synchronous lung metastases were observed in 3 patients, and 7 patients had metachronous metastases developing 9 to 121 months (median; 33 months) after primary tumor resection. Eight patients had solitary metastatic nodule in lung, while two patients had multiple lesions confined to unilateral lung. Five patients underwent wedge resections, 4 underwent pulmonary lobectomies, and one patient had both wedge resection and lobectomy in unilateral lung. Three patients were lost during the follow-up, but remaining 7 patients are alive after median follow-up of period of 32 months and 6 of these patients have no postoperative recurrence. In addition, four of these 7 patients are alive for more than 3 years after lung metastatectomy. CONCLUSION: Pulmonary metastasis from colorectal cancer without other organ involvement may be a candidate for lung resection. However, further studies are needed to determine the survival benefits after pulmonary resection.