We report a case of massive melena caused by a carcinoid of the small intestine. A 28-year-old woman was admitted to our department after presenting with massive melena. The source of the bleeding could not be localized by upper or lower gastrointestinal endoscopy, computed tomography (CT), or labeled red blood cell scintigraphy. Enteroscopy allowed visualization only up to the jejunum, and we could not localize the lesion. The melena subsided with conservative treatment, but the patient was readmitted 4 months later when she suffered another episode of massive melena. A contrast CT scan performed immediately showed extravascular leakage and the retention of contrast medium in the ileum. Thus, she underwent an emergency surgery, during which endoscopy confirmed a small ileal tumor accompanied by pulsating bleeding from the exposed blood vessels at its center. The small intestine was partially resected, including the swollen lymph nodes, the size of small beans. Pathological examination confirmed a carcinoid tumor 1 cm in diameter, with an arterial rupture at its center and lymph node metastasis.