We presented MR cholangiography (MRC) of congenital biliary malformations in infancy. MRC was obtained during induced sleeping. In two cases of congenital dilation of bile duct, MRC revealed cystic or spindle dilatation of intra- and extra hepatic bile ducts. In one biliary atresia, MRC revealed the serpentine gall bladder and cystic dilatation of the extrahepatic bile duct without connection to the dilated hilar bile duct. MR cholangiography, which can be obtained noninvasively, is useful for the diagnosis and the preoperative assessment of congenital biliary malformations in infancy.