Congenital mesenteric defect is a rare condition, of which the cause is unknown. Most articles regard it as an embryonal development defect. The mesenteric defect easily leads to internal herniation with possible intestinal obstruction or volvulus. Gangrenous change, sepsis, and death may occur. Most cases are diagnosed at the time of surgery, although the plain film and small bowel series may help in the diagnosis. Misdiagnosis as paralytic ileus and delay in surgical treatment are common because patients have no history of trauma or previous surgery. We report 5 cases of congenital mesenteric hernia collected during the past 11 years, and compare them with other reports.