Case Report: A 29-year-old gravida 4 para 3 was referred to evaluate a fetal intra-abdominal cyst at 34 weeks’ gestation. Fetal biometry was appropriate for dates and a cystic mass measuring 24 mm was visualized at the hepatic hilum, separate from the gallbladder and anterior to the kidney. On subsequent sonograms it increased in size measuring 37 mm at 39 weeks’ gestation. Differential diagnosis included choledochal cyst, biliary atresia, simple hepatic, ovarian, mesenteric or omental cyst, duodenal duplication cyst, adrenal or renal cyst and hydronephrotic pelvis. However its constant position in the porta hepatis narrowed the differential diagnosis down to choledochal cyst, biliary atresia and duodenal duplication cyst. A 3850-g girl was born by normal spontaneous vaginal delivery at 40 weeks’ gestation. There was no palpable abdominal mass and the infant passed normal green meconium. Total bilirrubin and liver enzymes were within normal limits. The infant fed well with no neonatal jaundice. On 10th day of life, ultrasound examination confirmed a probable choledochal cyst. At 106 days of life the infant underwent a laparotomy which confirmed the diagnosis of a choledochal cyst. Resection of choledochal cyst and cholecystectomy were performed followed by Roux-en-Y hepaticojejunostomy. Pathology was consistent with choledochal cyst. At 9-month follow-up the infant was healthy with normal growth. Most patients with choledochal cyst are asymptomatic until they present in the second or third decade of life with classic triad of abdominal pain, right upper quadrant mass and jaundice. When choledochal cysts present in the newborn period and are not treated, they are commonly associated with complications such as recurrent cholangitis, cirrhosis, portal hypertension, pancreatitis, liver failure and malignant transformation as a late complication. Early diagnosis can prevent above listed complications and clearly changes the prognosis of affected individuals favorably.