The prevalence of Helicobacter pylori infection in postoperative patients with biliary atresia (BA) was investigated in relation to esophageal varices, portal-hypertensive gastropathy (PHG), and peptic ulcer disease (PUD) in 25 Japanese patients (10 boys and 15 girls) aged from 16 months to 20 years. Gastric biopsy specimens obtained during endoscopy were used for both the rapid urease test and modified Giemsa staining. The patients were classified into three groups according to liver function: 15 in group A (total bilirubin [TB] < 1.0 mg/dl), 7 in group B (1.0 </= TB < 2.0 mg/dl), and 3 in group C (TB >/= 2.0 mg/dl). Esophageal varices were found in 19 patients (60% of group A and all patients in groups B and C) and PHG in 3 group B patients. However, no gastric or duodenal ulcers were found in any case. Only 2 patients (8%) had H. pylori colonization of the gastric mucosa. Both, however, belonged to group A, and the degree of chronic neutrophilic infiltration of the mucosal layer was as mild as that of the other patients. The prevalence of H. pylori infection and PUD in postoperative patients with BA was quite low, and a pathological relationship with the severity of liver disease could not be determined in these patients.