We designed a multicenter cross-sectional study to evaluate the role of alcohol abuse, the hepatitis viruses and other pathogenic factors in cirrhosis and hepatocellular carcinoma. A total of 1,829 consecutive cirrhosis patients, with or without HCC, was enrolled over 6 mo in 21 centers throughout Italy. The etiological categories and diagnostic criteria were preestablished. The median age of the patients was 59 yr (range, 13 to 85 yr); 63.6% of the patients were graded as Child class A, 23.4% as Child class B and 13% as Child class C. Hepatitis C virus antibodies were found in 72.1% of cases (47.7% alone, 21.2% with alcohol abuse, 3.2% with hepatitis B virus); HBsAg was present in 13.8% (4.2% alone, 3.2% with hepatitis D virus, 3.2% with hepatitis C virus, 3% with alcohol abuse), alcohol abuse with no concomitant viral infection was recorded in 8.7%, primary biliary cirrhosis was found in 1.8%, other causes were found in 1.4% and cryptogenic cirrhosis was only present in 5.3%. Hepatocellular carcinoma was detected in 11.9% of patients (217 cases). The presence of hepatocellular carcinoma was more frequent in males than females (14.7% vs. 7.3%; p < 0.001) and increased with worsening Child class (8.3% in Child class A, 16.9% in Child class B, 19.9% in Child class C, p < 0.001). The highest prevalences of hepatocellular carcinoma were observed in hepatitis B virus infection, with or without alcohol abuse (20% and 16%, respectively) and in hepatitis C virus cirrhosis, with or without alcohol abuse (16% and 10.3%, p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)