Biliary atresia is an obliterative cholangiopathy with progressive hepatobiliary disease, starting from the perinatal period. With a frequency of 1/15-18,000 live births, biliary atresia is the commonest cause of life-threatening liver disease in infants, and fatal if untreated. Prognosis is poor, unless early diagnosis is followed by surgical treatment. Clinical aspect, liver function tests, scintigraphy, histology, and increasingly, ultrasound techniques and endoscopic retrograde cholangiography are being used to discriminate other causes of neonatal cholestasis. Ten-year survival of children with biliary atresia, including those transplanted for end-stage liver disease, is up to 90%. Prognosis and outcome are largely dependent on early diagnosis and expert surgical management.