Congenital cystic dilatation of the intrahepatic biliary ducts, until recently, has been infrequently recognized. Three patients with this anomaly have been treated at Northwestern University Medical Center during the past five years. Review of the world literature has yielded an additional 81 cases. Operative cholangiogram has become the most valuable test for the diagnosis, location, and extent of the disease process. Hepatic lobectomy or segmental resection yields the best results. Internal drainage has been the most frequent surgical treatment performed. Because of recurrent episodes of cholangitis, prolonged postoperative therapy with antibiotics and careful follow-up study are required.