A total of forty patients with resected N2 stage non-small cell lung cancer treated with postoperative adjuvant radiation therapy between Jan. 1975 and Dec. 1990 at the Department of Radiation Oncology, Yonsei University College of Medicine, Yonsei Cancer Center were retrospectively analysed to evaluate whether postoperative radiation therapy improves survival. Patterns of failure and prognostic factors affecting survival were also analysed. The 5 year overall and disease free survival rate were $26.3\%,;27.3\%$ and median survival 23.5 months. The 5 year survival rates by T-stage were $T1;66.7\%,;T2;25.6\%;and;T3;12.5\%.$ Loco-regional failure rate was $14.3\%$ and distant metastasis rate was $42.9\%$ and both $2.9\%.$ Statistically significant factor affecting distant failure rate was number of postitive lymph nodes(>=4). This retrospective study suggests that postoperative radiation therapy in resected N2 stage non-small cell lung cancer can reduce loco-regional recurrence and may improve survival rate as compared with other studies which were treated by surgery alone. Further study of systemic control is also needed due to high rate of distant metastasis.