A mesenteric cyst is considered one of the rarest type of abdominal tumor. We have experienced unusual case oflarge mesenteric cyst arising from jejunum in a 10-year-old boy. CT disclosed cystic intrabdominal mesenteric masswith attenuated coefficiency +3-+11 Hounsfield units (HU). Pathologically it was confiremed to be benignmesenteric cyst.