A 83-year-old man presented at our hospital with hemosputum, and Stage III B(T4N3M0)lung cancer was diagnosed after thorough examinations. Although systemic chemotherapy was performed and kept the disease stable, anemia progressed. The fecal occult blood was recognized, and the enhanced abdominal CT scan revealed a 8 cm enhanced small intestinal tumor. Laboratory data indicated the presence of an inflammatory reaction(WBC 17, 970/mm3, CRP 1.38 mg/dL), and the serum granulocyte-colony stimulating factor(G-CSF)was elevated(104.0 pg/mL). A small intestinal tumor with hemorrhage and G-CSF production was diagnosed, and laparoscopy-assisted partial resection of the small intestine was performed. On histopathologic and immunohistochemical findings, the intestinal tumor was diagnosed as a small bowel metastasis originating from a primary lung cancer. After surgery, anemia progression stopped and WBC kept at a normal range. Although systemic chemotherapy was resumed because of performance status improvement, the disease progressed gradually. The patient received best supportive care and died about 9 months after the diagnosis of small bowel metastasis.