BACKGROUND The aim of the present study was to determine the rate of early-onset biliary atresia (BA) and its implications, for embryonic-type BA in Taiwan, a high-prevalence area for BA. The relationship between the timing of disease onset and congenital extrahepatic anomalies was also identified. METHODS Medical records of 130 infants born in Taiwan with biliary atresia between January 1996 and December 2005 were reviewed retrospectively. The gold standard for the diagnosis of biliary atresia was intraoperative cholangiography. As well as medical records review, abdominal imaging and echocardiograms were performed to determine other structural anomalies. Early-onset BA was defined as acholic stool and cholestatic jaundice observed before 2 weeks of age. RESULTS On review of onset of acholic stool and cholestatic jaundice before 2 weeks of age, 31 patients (23.8%) were defined as having early-onset BA. Twenty patients (15.4%) had major congenital extrahepatic anomalies. One (0.7%) had biliary atresia splenic malformation syndrome (BASM). Both early-onset and late-onset BA may be associated with other structural anomalies. Patients with early-onset BA had a higher probability of having major extrahepatic anomaly (9/31 vs 11/99, P = 0.046). Situs anomalies accompanying major gastrointestinal (GI) tract anomalies occurred only in early-onset BA patients. CONCLUSIONS After comprehensively investigating the timing of onset and associated congenital extrahepatic anomalies in BA patients in Taiwan, only one BASM with double spleen was detected. A total of 23.8% of patients had early-onset BA, and this group of patients is prone to extrahepatic anomalies. Situs anomalies accompanying major GI tract anomaly may be indicative of embryonic-type early-onset BA.