Blunt abdominal trauma is commonly encountered in the emergency department. The lack of historical data and the presence of distracting injuries or altered mental status, from head injury or intoxication, can make these injuries difficult to diagnose and manage. We experienced a case of traumatic organized hematoma misdiagnosed as intra-peritoneal tumor with intestinal obstruction. A 52-year-old homeless male patient who have chronic alcoholism was admitted via emergency room with infra-umbilical abdominal pain. At admission, he was drunken status and so we could not be aware of blows to the abdomen. He had a unknown large operation scar on mid abdomen. A computed tomography (CT) scan showed the intestinal obstruction of the ileum level with 5.5cm sized mesenteric tumor. We performed adhesiolysis and widely segmental resection of small bowel including tumor with side-to-side anastomosis due to great discrepancy in size. He stated later that he was a victim of the violence before 3 weeks. A final pathologic report revealed well encapsulated, traumatic mesenteric hematoma with organizing thrombi, ischemia and abscess formation with multiple adhesion bands. Finally, the patient was discharged without complications on postoperative day 14.