To assess the degree of fibrosis and the structural changes affecting parenchymal and extraparenchymal components in liver cirrhosis, a computerized morphometric model has been applied to liver specimens from patients with posthepatitic and alcoholic cirrhosis. All specimens have been stained with chromotrope-aniline blue method and monoclonal antibodies against cytokeratin 7, CD31, and VIII factor. Volume fractions of parenchymal compartment and fibrosis have been determined stereologically on CAB slices; moreover, volume fractions of portal bile ducts and proliferated bile ductules, hepatocytes with biliary metaplasia, capillary units, and vascular structures have been measured. Volume fraction of fibrosis was higher in alcoholic cirrhosis when compared with the case of posthepatitic cirrhosis. Volume fractions describing parenchymal compartment showed a similar trend in both viral groups. The main differences were related to immunohistochemical stainings. Volume fraction of hepatocytes with biliary metaplasia was higher in hepatitis C virus-related cirrhosis, whereas volume fractions of biliary structures were more prominent in hepatitis B virus-related cirrhosis. Capillary units were more prominent in posthepatitic cirrhosis than in alcoholic cirrhosis. Interestingly, both forms of posthepatitic cirrhosis show similar features when compared with alcoholic cirrhosis. Our computerized morphometric model well describes and quantifies the morphological alterations of the liver, and it could represent an adjunctive tool to evaluate the degree of dysplastic phenomena involving parenchymal and extraparenchymal components.