Metastatic carcinoma from primary lung cancer is usually recognized in the brain, adrenal glands, and bone. It is uncommon in the digestive system, particularly in the duodenum. We report a 63-year-old man who had undergone a left lower lobectomy for lung cancer. Anemia (Hb 6.9 g/dl) had been observed 2 months after surgery for primary lung cancer. Gastroduodenoscopy showed duodenal metastasis, and further examination demonstrated adrenal metastasis. Palliative treatment was selected and the patient died 5 months after surgery.