Objective: To explore the distribution of biliary ductules in biliary remnants of patients with biliary atresia and to investigate the relationship between the ductules and the prognosis after Kasai portoenterostomy. Patients and methods: From October 01, 2015 to September 30, 2017, 46 patients who were diagnosed as type 3 biliary atresia were enrolled in this study. Continuous sections of biliary remnants were stained with cytokerantin 19 antibody. The number, area, and distribution of micro-biliary ductules of each section were recorded. According to the number of ductules in themost proximal section (n similar to 20 or n < 20), patients were divided into two groups (A or B) and followed up for 1-3 y, including cholangitis, jaundice clearance, and survival with native liver. Results: Four patients had no micro-biliary ductules. In 17 patients with ductules, the numbers at bilateral parts were similar (P > 0.05), while the ductules in the middle part were significantly less than bilateral parts (P < 0.05). Starting from 2 mm from the proximal end of remnants, the number of ductules significantly and gradually decreased (P < 0.05). The total area of ductules in Group A was significantly increased compared to that in Group B (P < 0.05). Patients in Group A had significantly higher jaundice clearance rate and better survival rate with native liver than patients in Group B (both, P < 0.05). Patients had significantly higher incidence of cholangitis in Group A compared to Group B (P < 0.05). Conclusions: The number/area of ductules yielded by technical precision is closely related to effective bile drainage, jaundice clearance, and first onset of cholangitis in patients after Kasai procedure. (C) 2019 Elsevier Inc. All rights reserved.