Abdominal lymphangiomas are uncommon angiomatous tumor occurring mainly in childhood. This is a retrospective clinicopathologic study of 17 cases of abdominal lymphangioma. The patients included are five children and 12 adults, with a mean age at initial presentation of 30.7 years (age ranges 3-63). The locations of the tumors were mesentery (5), retroperitoneum (4), colon (3), omentum (3), mesocolon (1) and gallbladder (1). Infiltrative growth was more common pattern than entirely circumscribed pattern. Masses were mostly multilocular cysts and contained chyle or serous fluid. On immunohistochemical staining, 16 cases were reactive for either CD31 or factor VIII-related antigen. These fact would suggest that intra-abdominal lymphangiomas simulate the immunohistochemical features of collecting lymphatics. Follow up was possible in 12 cases for 3-50 months (mean 19 months) and only one patient showed local recurrence. Although abdominal lymphangiomas are rare in adulthood and correct preoperative diagnosis is difficult, awareness of such a possibility in adulthood will contribute to make a correct preoperative diagnosis.