Objectives: To investigate the incidence, presence of associated anomalies, type of malformation, and natural history of children with biliary atresia (BA) who presented antenatally. Study design: The database of 194 infants diagnosed with BA at our tertiary referral unit between 1991 and 2002 was reviewed for infants in whom routine antenatal ultrasound had revealed biliary cystic malformations (BCMs). A retrospective analysis of their medical records was undertaken. Results: Nine infants (six girls) with BCM were identified (4.6% of total referred patients with BA); all were born after 37 weeks' gestational age and presented to us at a median age of 4 weeks (range, 1-14 weeks). The presence of the BCM was confirmed on postnatal ultrasonography. Median age at corrective surgery was 5 weeks (range, 2-16 weeks). At surgery, six patients had type III BA, including one with the biliary atresia-splenic malformation syndrome; two had type II BA; and one had type I BA. Postoperatively, the infants were followed for a median of 2 years (range, 6 months to 11 years). All infants successfully cleared their jaundice. Conclusions: Improved techniques in routine antenatal ultrasonography can allow early recognition of BCM. This study suggests that BCM noted antenatally may represent early presentation of both biliary atresia-splenic malformation and nonsyndromic BA.