Biliary atresia is the most common cause of end‐stage liver disease in the infant and is the leading pediatric indication for liver transplantation in the United States. Earlier diagnosis (<30‐45 days of life) is associated with improved outcomes following the Kasai portoenterostomy and longer survival with the native liver. However, establishing this diagnosis is problematic because of its rarity, the much more common indirect hyperbilirubinemia that occurs in the newborn period, and the schedule for routine infant health care visits in the United States. The pathogenesis of biliary atresia appears to involve immune‐mediated fibro‐obliteration of the extrahepatic and intrahepatic biliary tree in most patients and defective morphogenesis of the biliary system in the remainder. The determinants of the outcome of portoenterostomy include the age at surgery, the center's experience, the presence of associated congenital anomalies, and the postoperative occurrence of cholangitis. A number of screening strategies in infants have been studied. The most promising are early measurements of serum conjugated bilirubin and a stool color card given to new parents that alerts them and their primary care provider to acholic stools. This report summarizes a National Institutes of Health workshop held on September 12 and 13, 2006, in Bethesda, MD, that addressed the issues of outcomes, screening, and pathogenesis of biliary atresia. (HEPATOLOGY 2007;46:566–581.)