We treated surgically 567 patients with primary lung cancer from June 1975 to December 1989. There were nine patients with advanced (p-stage III.IV) lung cancer less than 2.0 cm in size. The five year survival rate was 50.8%. The histological diagnosis was adenocarcinoma in 6, squamous cell carcinoma in 3. A curative resection was performed in seven of nine patients. Six patients had one level metastasis of mediastinal lymph node. Three patients in whom relative curative resection was performed at surgery later developed regional recurrence. However, distant metastasis was not evident in all but one of nine patients. In conclusion surgical resection is considered to be significant in patients with advanced (p-stage III.IV) lung cancer less than 2.0 cm in size.