The prevalence and type of portal hypertension (PH) in primary biliary cirrhosis (PBC) and their relationship with liver lesions have been investigated in 32 patients with the disease. Portal hypertension was considered when oesophageal or gastric varices were observed by endoscopy and/or when hepatic venous pressure gradient measured by hepatic vein catheterization was greater than 6 mmHg. Within 3 days of endoscopy, a liver biopsy was performed for histological staging and semiquantitative grading (0 to 3+) of portal and sinusoidal fibrosis, portal inflammation, piecemeal necrosis, lobular necrosis, cholestasis, as well as the presence of granulomas and Mallory's hyaline. Twenty patients (62.5%) had portal hypertension, five of them showing presinusoidal PH (15.5%) and the remaining 15 (47%) with sinusoidal component. The four patients in stage IV had sinusoidal PH and the only patient in stage I had no PH. The prevalence of portal hypertension was similar in patients in stage II (57%) and stage III (55%), but presinusoidal PH was only observed in patients in stage II. Patients with PH showed significantly higher portal inflammation and piecemeal necrosis than patients without PH. By contrast, there were no differences in portal and sinusoidal fibrosis, nor in the other histologic features. These results indicate that portal hypertension is common in PBC and it may be present in the early stages of the disease. The fact that presinusoidal PH was only observed in patients in stage II suggests that portal hypertension is initially of presinusoidal type, and then as the disease progresses is joined by a sinusoidal component.