Choledochal cyst is a cystic or fusiform dilatation of the extra- or intrahepatic bile duct that has rarely been reported in prenatal cases. Here we report a fetus with choledochal cyst diagnosed prenatally by three-dimensional (3-D) ultrasonography at 22 weeks of gestation. We demonstrated an image of choledochal cyst by using a new ultrasound technique, a 3-D multislice view. After close intrauterine followup, surgery was successfully performed and postoperative course was uneventful.