Case 1: A 66-year-old man who had undergone upper right lobe resection for large cell lung carcinoma 2 months earlier presented with abdominal pain and vomiting. Computed tomography showed intussusception of the small intestine. Partial resection of the small intestine was performed. The tumor was pathologically diagnosed as lung cancer metastasis to the small intestine. The patient died 30 days after surgery. Case 2: A 57-year-old man was admitted to hospital due to appetite loss. Computed tomography showed a large intestinal tumor and a small lung tumor, as well as multiple liver metastases and lymph node metastases. We diagnosed perforation of the small intestine tumor, and partial resection of small intestine was performed. Pathological examination and immunohistochemical staining revealed that the tumor was a metastatic adenocarcinoma, and the patient was diagnosed with small intestine metastasis of lung cancer. He died 75 days after surgery. Although small intestine metastasis of lung cancer is rare, the incidence is increasing. The prognosis of lung cancer metastasis of the small intestine is poor, and therefore, we must urgently decide the appropriate treatment.