A resection of pulmonary metastases from colorectal cancer was performed in 27 patients. The cumulative 5-year survival after thoracotomy was 41.1%. Patients with either one or two metastases had a significantly better survival, with a 5-year survival of 54.3%, than did those with a greater degree of metastases (p < 0.01). Other factors including the disease-free interval, size of metastases, type of pulmonary resection, and stage of primary cancer had no apparent influence on post-thoracotomy survival. Furthermore, the presence of controlled hepatic metastases had no adverse effect on survival and did not seem to contraindicate pulmonary resection. The lung and primary colorectal region were the major sites of recurrence. Therefore, the primary colorectal site should be explored thoroughly and the number of metastases should be carefully considered when pulmonary resection is considered for metastatic colorectal cancer.