Sixty-one patients with completely resected non-small cell lung cancer followed by postoperative radiotherapy were retrospectively reviewed. Forty-six patients were male and 15 were female. Ages ranged 34-79 (median 64) years. Squamous cell carcinoma (scc) in 28, adenoca. in 31, large cell ca in 1 and adenoid cystic ca. in 1. Pathological stage was IIA in 1, IIB in 9, IIIA in 41 and IIIB in 10. Over-all 5-year survival rate (OS) was 56.0%, and 5-year disease-free survival rate (DFS) was 39.7%. For IIB, IIIA, IIIB patients, OS were 77.8%, 55.4%, 24.0% respectively. According to purpose of radiotherapy, patients divided into 3 types as local invasion (LI) group (T3-4N0-1, n = 12), lymphnode metastases (LN) group (T1-2N2-3, n = 38) and both advanced (BA) group (T3-4N2-3, n = 8). OS were 71.6%, 50.7%, 46.9% and DFS were 68.6%, 31.0%, 42.9% respectively. In LN group, half of patients with scc had no relapse, but about half of non-scc had distant metastases. All N2 patients divided 2 types as single-station N2 and multi-station N2. OS were 71.8%, 40.0% and DFS were 53.5%, 21.1% respectively. DFS was significantly different (p = 0.04). The advantage was remarkable in patients with scc-single-station N2 (OS was 88.9%, DFS was 77.8%). The effectiveness of postoperative radiotherapy is not showed, but our results suggest the possibility for existence of subgroup benefited from postoperative radiotherapy.