Four forms of piecemeal necrosis—biliary, lymphocytic, ductular, and fibrotic—were identified in 605 liver biopsy specimens from 209 patients with primary biliary cirrhosis. Whereas lymphocytic piecemeal necrosis, often associated with lobular hepatitis, was most common in stages 2 and 3 of the classical histologic staging, biliary piecemeal necrosis was frequent in all stages, except stage 1, and the fibrotic form appeared to be a late, mainly cirrhotic feature. In 77% of patients cholestatic features predominated, whereas hepatitic changes producing some histologic overlap with chronic active hepatitis occurred in the remaining patients. These patterns tended to be maintained throughout the course of the disease. Large hypocellular scars found in 36% and 59% of stage 3 and 4 specimens, respectively, appeared to be a characteristic feature of biliary disease. The prevalence of classical features was assessed. The analysis of sequential biopsy specimens from those patients who died showed that cirrhotic transformation, increasing cholestasis (in particular with prominent hyaline inclusions), abundance of coarse collagen bundles, and “halo” formation at the margins of the fibrous septa were associated with a poor prognosis. We were unable to show that the presence of granulomas is associated with a more favorable course of the disease.