It has been reported that chronic alcoholics show a high prevalence of hepatitis C virus (HCV) infection, with a possible role in the pathogenesis and severity of underlying liver disease. Thus, the present study was aimed to evaluate the prevalence of HCV antibodies (anti HCV-Ab) in a group of patients admitted to an Internal Medicine Department, as well as to compare characteristics of anti-HCV-Ab(+ve) respect to anti-HCV(-ve) patients. The presence of anti-HCV-Ab was prospectively studied in 180 alcoholic patients admitted during a 16-month period using a second generation ELISA. Intravenous drug abusers were excluded. Reasons for admittance were as follows: alcohol withdrawal syndrome (92 cases), complications of liver cirrhosis (mainly ascites) (54 cases), acute pancreatitis (12 cases) and miscellaneous causes (22 cases). Sixty-six patients were cirrhotics, 23 had fatty liver, 27 had liver fibrosis and 28 alcoholic hepatitis (36 patients were not evaluable concerning liver lesion). Twelve patients (6.7%) were anti-HCV-Ab(+ve). Prevalence was higher in patients admitted because of complications of cirrhosis (16.7%) than that of those admitted due to alcohol abstinence syndrome (1.1%, p < 0.01). Likewise, the proportion of HVC-Ab(+ve) patients was higher in patients with liver cirrhosis (16.7%) respect to those with lesser degrees of liver injury (1.3%; p < 0.01). In the latter group, the prevalence of anti-HCV-Ab(+ve) was similar to that of the normal population. Anti-HCV-Ab patients were older than anti-HCV-Ab(-ve) cases.(ABSTRACT TRUNCATED AT 250 WORDS)