Hepatic artery resistance index has been measured by ultrasonography Doppler and has been found to predict rapid deterioration and death in children with biliary atresia. Clinical, biochemical, ultrasonographic, and outcome data were collected prospectively and retrieved on 32 patients with resistance index of H1.0 (group A). These were compared with the same data for 32 age-and sex-matched patients with biliary atresia and a resistance index of F1.0 (group B). Group A was found to have significantly worse liver function tests than group B. In group A, all patients died (n โซุโฌ 11) or underwent transplantation (n โซุโฌ 21; of whom 4 died) compared with only 2 patients who died in group B and 4 patients who underwent transplantation without fatality. Survival at 2 years was 52% in group A v 94% in group B. It is suggested that regular ultrasonography Doppler examination in patients with biliary atresia can detect a group with a resistance index of G1.0 who have a very high risk of early mortality. Such patients require early evaluation and listing for transplantation. Those listed for liver transplantation on other grounds require ultrasonography examinations every 2 to 3 months with immediate upgrading of the priority of those patients found to have a resistance index of H1.0.