Biliary atresia(BA), the most common cause of obstructive jaundice in infancy, has been considered to be a result of progressive destruction of the bile ducts through a necroinflammatory process. Many immunohistochemical studies of BA remnant have been done, but it has not been shown that biliary epithelial cells (BECs) can be cultured from BA remnant. For this study, we obtained bile duct remnants from three patients with biliary atresia (one male, two females) who received Kasai's operation from 2002 to 2003. The successive cultivation rate of BECs from explants was 100% (3/3 patients). Culture of BECs on collagen gel was possible up to at least four passages. Under a phase-contrast microscope, primary and passed cultured cells on collagen gel showed a cobblestone-like spread in 2 weeks. The BECs had immunoreactivity to anti-human cytokeratin 7 antibody. In this study, we proved that BECs in the remnants of BA could be cultured, and defined the maturation of biliary epithelial cells of BA by immunocytochemistry with anti-human cytokeratin 7 antibody. In conclusion, BECs in BA remnant are "alive", and their proliferation activity can be maintained.