Liver involvement with a variety of viral diseases is a frequent finding in chronic renal failure patients on regular hemodialysis treatment. We evaluated the prevalence of IgG anti-hepatitis C virus antibodies (HVC) in our dialysis unit, looking for risk factors associated with seropositivity and we assessed the type and degree of liver involvement by means of a liver biopsy in those patients with biochemical abnormalities of liver function test. We studied 50 patients aged 13 to 77 years, and performed serial determinations of serum ALT (UI/L). IgG anti HVC was determined by a second generation ELISA Kit (Abbot). We retrieved information from chart review and patient interview, regarding: time on hemodialysis, number of blood transfusions and intravenous IV drug use off dialysis. Liver biopsy specimens were stained with H.E. and Masson and findings were classified as chronic persistent, chronic active hepatitis or cirrhosis, according to Schewer. We compared the findings with those of other patients with liver dysfunction and positive IgG anti HVC who did not have renal failure. Anti-HVC prevalence in our hemodialysis patients was 44%. Anti-HVC seropositive hemodialysed (HD) patients were not different from seronegative HD patients, with regard to age, sex, i.v. drugs usage and peak ALT values. Twelve of 22 HVC positive patients had peak ALT values higher than 40 UI/L (Table 2). Time in HD (75.5 +/- 42.8 m) and number of blood transfusions received (35.3 +/- 28) were clearly different in HVC positive patients, compared to HVC negatives. Histologically, 11 seropositive patients showed chronic persistent hepatitis as the most frequent finding.(ABSTRACT TRUNCATED AT 250 WORDS)