The authors report a case of acute intestinal bleeding caused by ulcerated segmental ileal dilatation occurring in a 5-month-old infant. The profuse emission of dark red blood per rectum caused acute anemia (Hb 5.3 g/dL). Because of absence of any other sign and symptom and normal plain x-ray, a bleeding Meckel's diverticulum was suspected. Laparoscopy was performed showing the ileal dilatation, and through an enlarged port incision the bowel was exteriorized and resected. Histology results showed an ulcer caused by heterotopic gastric mucosa. The etiopathogenesis and clinical manifestations of segmental intestinal dilatation are discussed.