OBJECTIVE Prospectively achieved findings of 151 children with EHBA operated between 1972-1997, of 108 patients in particular who were operated five and more years ago, should give evidence of the efficiency of HPE. METHODS For five and more years the development of the disease was prospectively evaluated according to a cognitively conditioned program. The objective source parameter was the hepatic histology at the time of surgery. Departing from that parameter the structural hepatic changes were followed up for five years and more. They were related to the bile flow achieved and the age of the patient, at the time of surgery as well as to the present time of follow-up. RESULTS Of 108 patients who were operated five and more years ago, 62 are still alive (57%) 58 children are icterus-free. The following results can be stressed: 1) There is a close correlation between the age of the patient and the fibrosis level of the liver at the time of surgery. 2) There is a close correlation between the age and the fibrosis level at the time of surgery on the one hand and the long-term survival rate, the absence of icterus and the state of the hepatic function on the other. 3) There is a close correlation between the age and the fibrosis level at surgery on the one hand and the operatively feasible (continued) bile flow on the other. 4) With favorable conditions concerning age and fibrosis level at the time of surgery, the size of the bile flow achieved through surgery is influenced positively and negatively by the morphology and bio-physical parameters of the porta hepatis as well as by postoperative cholangitis episodes. CONCLUSIONS The efficiency of HPE depends on the age and (in correlation to that) on the level of hepatic fibrosis at the time of surgery, on the morphology and on bio-physical properties of the porta hepatis as well as on cholangitis episodes occurring after surgery. The fibrosis level of the Glisson's triads at the time of surgery, the morphology and bio-physical parameters of the porta hepatis are documented as causes for failing or discontinued bile flow after HPE and for the progression of fibrosis. In the absence of obvious causes it is postulated that the initially obliterating and continuing primary disease has progressed. The performance of the HPE is summarized in the results: of 108 children who were operated five and more years ago 62 are still alive, 58 are icterus-free, 25 show no progression of fibrosis and 46 of 82 patients who were initially cirrhosis-free have no cirrhosis at present.