Biliary atresia (BA) remains one of the most intractable liver diseases in pediatric population. In this project, we conducted 3 studies regarding its pathophysiology. In study 1, serum levels of IL-12, IL-18, and IFN-gamma were determined from 46 BA patients and 19 normal controls. We found that serum IL-18 and IFN-gamma levels were increased in BA. The elevated serum IL-18 in BA patients was associated with worse clinical outcome. These suggest that IL-18 and IFN-gamma play roles in the pathophysiology of BA. In study 2, survivin and caspase-3 expression was determined using immunohistochemistry from liver biopsies of 49 BA patients, and 29 non-BA pediatric patients. We demonstrated that survivin expression of biliary ductular epithelia was related to BA. These suggest that actions of survivin proteins involve in the biliary pathology of BA. In study 3, ninety-four BA patients between 2001 and 2009 were reviewed. Serum total bilirubin (TB) was determined at 7th day after surgery. The data shown by evaluation of serum TB at 7th day after surgery showed a prognostic power to predict a short-term surgical outcome at 6th month.