A 39-year-old woman who had a two-year history of right upper quadrant abdominal mass was admitted. Abdominal ultrasonography and computed tomography revealed a large, multiloculated cystic tumor in the liver. This tumor was noted with elevated levels of carcinoembryonic antigen (CEA) (397 ng/mL) and carbohydrate antigen (CA)19-9 (24,000 U/mL) in the cystic fluid and elevated serum CA19-9 level (438 U/mL). A 18×15×6 cm, 1,220 gm cystic mass was removed by cystectomy. The cut section revealed a multilocular cyst containing yellowish mucinous fluid surrounded by a smooth and glistening wall. It was diagnosed histologically as an intrahepatic biliary cystadenoma with mesenchymal stroma, which consisted of single layer of a cuboidal epithelial lining and an ovarian-like stroma. Six weeks after surgery, the serum CA19-9 level was decreased to 59 U/mL. These findings may be useful in the differential diagnosis of intraheptic cystic tumors and thus, we report this case with a review of the literatures. (Kor J Gastroenterol 2000;36:122 - 127)