This article reviews the clinical characteristics of seven synchronous multiple primary lung cancer cases seen at the Seoul National University Hospital between the July of 1986 and the December of 1989. All seven patients were male with the mean age of 64. All were smokers, most of them were heavy smokers with the mean of 66.7 pack-years of smoking history. The tumors were of the same histologic type in five cases (all were squamous cell carcinoma). different in one case (squamous cell carcinoma and small cell carcinoma), and undetermined in one case (squamous cell carcinoma and non-small cell carcinoma). Fiberoptic bronchoscopy was a very useful tool in diagnosing multiple primary lung cancer. Surgical resection could be done in only one case.