The epidemiology of non-A, non-B hepatitis (NANBH) is still incomplete. To define the prevalence of antibodies against the main causative agent of NANBH, the hepatitis C virus (HCV) and the role of some risk factors, we tested sera from 269 patients on chronic dialysis at the hemodialysis units in our region in central Italy. We utilized the recently developed serological assay. Twenty-nine hemodialysis patients (13.3%) and 3 peritoneal dialysis patients (4.8%) were anti-HCV positive. Of these, 13 (40.6%) had antibodies to hepatitis B core antigen (anti-HBc) indicating prior hepatitis B infection. The anti-HCV seropositive patients had been on dialysis longer than the seronegative ones; they had received more transfusions than the others but without a significant difference. The prevalence rate of anti-HCV was statistically significantly higher among hemodialysis patients utilizing the same dialysis equipment for the previous 12 months.