Seventy patients with biliary obstruction secondary to hilar tumors underwent attempted endoscopic internal biliary drainage using large transpapillary stents between December 1981 and March 1986. Placement of one or more stents was successful in 68. The type of stricture and mode of treatment were more important in determining subsequent survival than the type of tumor. In type II and III malignant strictures of the bifurcation of the common hepatic duct and the main hepatic duct, use of two or more stents to achieve complete drainage of the biliary system improves survival compared to incomplete drainage (176 vs. 119 days) and reduces procedure-related mortality and the incidence of early and late cholangitis. Patients with hilar tumors causing type II and III strictures treated with placement of multiple stents have at least as good a prognosis as patients with tumor involving only the common hepatic duct treated with use of a single stent. Once ERCP is performed and palliative endoscopic management of bifurcation tumors is begun, it must completed as soon as possible.