Biliary atresia is the leading cause of morbidity and mortality from pediatric liver disease and it is the most common indication for pediatric liver transplantation. Despite its clinical importance, little is known of a wide range of fundamental issues regarding biliary atresia. Viral and genetic causes of biliary atresia have been explored, yet its etiology remains fundamentally unknown. A lack of prospective clinical follow-up of children with biliary atresia has resulted in a relative poor understanding of its natural history. Evidence based approaches to the medical and surgical management of biliary atresia do not exist, in large part due to an absence of prospective multi-centered studies. The Biliary Atresia Clinical Research Consortium is an outstanding mechanism for advancing the study of biliary atresia. Its concept is based upon the hypothesis that support of an international multi-centered research consortium of biliary atresia will permit valid studies of the etiology, natural history and treatment of biliary atresia. The Mount Sinai Biliary Atresia Study Group will consist of a pre-existing clinical consortium of twelve centers located in New York, New Jersey, Connecticut and Puerto Rico. This study group proposes the following three specific aims for the Biliary Atresia Clinical Research Consortium: Aim 1: Establishment of a biliary atresia database and serum/tissue bank:A prospectively collected clinical database and bank of serum and tissues from children with neonatal cholestasis is of absolute critical importance to advancing our understanding of biliary atresia. Aim 2. Prospective analysis of children with biliary atresia without a hepatoportoenterostomy or with a failed hepatoportoenterostomy:Prospective analysis of these patients will be performed in order to determine the reasons for these failures and to determine the optimal approach to their liver transplantation. Aim 3. Randomized trial of beta-blockade in the prevention of complications of portal hypertension in children with EHBA.Infants between 6 and 9 months of age will be randomized to receive beta-blocker therapy or placebo and complications of portal hypertension will be assessed prospectively.