Biliary mucinous cysiadenocarcinoma is a rare cystic tumor in the biliary system. It originates from biliary cystadenoma and symptoms such as aMominal pain, nausea, vomiting, jaundice, ascites, weight loss can be seen. Its prognosis is better than that of hepatoma or cholangio-carcinoma. Diagnosis is done by abdominal sonography, computerized tomography, percutaneous cholangiography or endoscopic retrograde cholangiopancreatography and shows multiloculated cystic mass with profuse ucus secretion. But confirrnatory diagnosis is done by surgical pathology that shows typical papillary projection of epithelial cell, dissruption of basernent mernbrane and mitotic figure. Treatment of choice is the radical resection of the tumor mass with nearby hepatic lobes and careful attention to prevent leakage of mucinous contents of tumor is needed. We report three cases of intrahepatic biliary mucinous cystadenocarcinoma diagnosed by postoperative pathology with review of other literatures. (Korean J Gastroenterol 1997; 30:837 -843)