A 47-year-old male was admitted to our hospital, and underwent an exploratory laparotomy with small intestinal resection due to suspected small intestine intussusception. The pathology of the intestine showed metastatic poorly differentiated carcinoma. CXR showed a mass in the left lower lobe of the lung, and adenocarcinoma was proved by bronchoscopic biopsy. After consulting with the pathologist, adenocarcinoma of the lung with small intestinal metastasis was diagnosed. Intestinal metastasis was found in 11% of lung cancers at autopsy, but it rarely produced symptoms. However, intestinal metastasis may produce gastrointestinal perforation, obstruction, bleeding and intussusception. Surgery may palliate the symptoms of some patients, however, the prognosis is poor.