Mesenteric cysts are rare intraabdominal benign cystic lesions. These lesions are most commonly located in the ileal mesentery, without any sex predilection. Mesenteric cysts may be totally asymptomatic and discovered incidentally during routine radiologic examinations. Chronic abdominal pain or acute abdomen may be accompanying to these lesions. Ultrasonography, computed tomography and magnetic resonance imaging are valuable in the diagnosis. Rarely, these lesions may be presented with rupture after trauma. We present a patient with a ruptured ileal mesenteric cyst due to a blunt abdominal trauma and diagnosed by emergency laparotomy.