Biliary atresia is a serious liver problem that occurs in young infants. It involves a problem with the bile ducts (the tubes through which bile drains from the liver into the small intestine). In children with biliary atresia, bile ducts are damaged, missing, or not shaped correctly. Treatment must be done as soon as possible. Biliary atresia is treated with surgery. Even if this surgery goes well, the child will likely need a liver transplant sometime in the future.