Biliary atresia (BA) is a common cause of infantile cholestasis. Disease progression leads to intra hepaticfibrosis, and thus to the development of PH and EV. Our objective has been to study the relationship between procollagen-III-peptide (PIIIP) and the severity of EV in children with BA after Kasai operation. Children below 15 years of age (n=29) with BA after a Kasai operation were evaluated for EV by endoscopy. Healthy (n=26) children of the same age and sex distribution who participated in the hepatitis B vaccination program served as the controls. Serum PIIIP was determined by radioimmunoassay. The BA patients were classified on the basis of severity of EV (Paquet's classification) into three groups: group 1 (n=15) had grade 0, group 2 (n=8) grade 1-2, and group 3 (n=6) grade 3-4 EV. In group 3, serum PIIIP (2.9 +/- 1.3 IU/ml) was significantly higher than in group 2 (1.5 +/- 0.4 IU/ml) (P < 0.05). Serum PIIIP levels were increased in group 2 compared with group 1 (1.2 +/- 0.4 IU/ml) and in group 1 compared with the control group (1.2 +/- 0.2 IU/ml), but this difference was not significant. PIIIP levels increased with severity of the EV in the BA patients. Hence, high PIIIP levels may serve as a non invastive indicator of EV developing in postoperative BA patients.