The incidence of multiple primary cancers is low than that of single primary cancer. In gastric cancer, incidence of occurrence of multiple primary cancer is 3 to 11.3%. Because stomach and lung are unrelated organs, the combination of gastric cancer and lung cancer is rare. Its estimated incidence is about 10% of all multiple primary cancers. The histologic types of secondary lung cancer in one series, squamous cell carcinomas were 49%; adenocarcinomas were 28%; large cell carcinomas were 14%; small cell carcinomas were 9%; others were 6%. This patient had been diagnosed as early gastric cancer 3 years ago, but he refused operation for cancer and wasnt followed up. After 3 years, he revisited us for dry coughing and diagnosed as small cell lung cancer. At this time, previous gastric cancer was remained as well differentiated, early gastric adenocarcinoma. For its rarity, we report this case with review of literatures.