The new stage of metastatic lung cancer based upon resectability, disease-free interval, and the number of pulmonary metastases was proposed in 1998 by Ginsberg, et al. We evaluated the validity of the new staging proposal for pulmonary metastases through the analysis of experiences at Severance Hospital. Material and Method: The cases of 111 patients who underwent resection of metastatic lung cancer during the eleven-year period (1990-2000) were reviewed. Of these patients, 103(92.8%) underwent compete surgical resection. The primary tumor was carcinoma in 60 cases, sarcoma in 46, and others in 5. The disease-free interval(DFI) was 0 to 35 months in 79 cases adn more than 36 months in 32 cases. Single metastasis accounted for 53 cases and multiple lesions for 58 cases. Mean follow-up was 49 months. Result: The actuarial survival after complete metastasectomy was 48.2% at 3 years and 32.6% at 5 years; the corresponding values for incomplete resection were 21.9% at 3 years. The 3-year survival rate(3-YSR) for complete resction was 40.5% and 5-year survival rate(5-YSR) was 30.4% for patients with a DFI less than 36 months, the 3-YSR, 75.8% and 5-YSR, 39.0% for those with a DFI equal or more than 36 moths; 45.8% and 30.5% for single lesions, 50.0% and 34.4% for multiple lesions. The 3-YSR and 5-YSR were 58.5% and 43.8% for stage I patients, 54.0% and 37.4% for stage II, 38.2% and 27.9% for stage III and 21.9% for stage IV. Conclusion: The result of the analysis of new stage of pulmonary metastases showed that the survival rate was different according to stage and there was no statistical significance. We need more experiences and long-term follow up to determine the prognostic factor of metastatic lung cancer surgery.