The prevalence of hepatitis C (HCV) antibodies in dialysis patients is considerably higher than that found among healthy blood donors. This increased seroprevalence has been correlated to increased duration of dialysis, mode of dialysis and to the number of blood transfusions administered. However, factors other than nosocomial ones also seem to play a part in disease transmission. The role of the patient's ethnic origin, possibly reflecting on his/her genetic makeup has received scant attention. In this study, HCV seroprevalence in our dialysis population, which consists of three major ethnic subgroups (Ashkenazi Jews, Sephardi Jews and Arabs), was examined. Altogether HCV seropositivity was determined in 120 dialysed patients—65 males/55 females (76 hemodialysis, 44 CAPD), using second generation ELISA confirmed by RIBA-2. Mean age was 59.7±15.7 (range 16–86 years). Patients had to have been on dialysis for a minimum of 3 months (mean duration 45.2±44.5 months). Patients whose end-stage renal disease was due to diabetic nephropathy (DN) or those who had previously been transplanted (TP) were considered as separate groups and compared to the group as a whole. Of the 120 patients, there were 49 Ashkenazi Jews (40.8%), 57 Sephardi Jews (47.5%) and 14 Arabs (11.7%). Overall HCV prevalence was 21.7% (26/120) with a significantly greater prevalence in HD compared to CAPD (30.3 vs. 6.8%, P>0.01). Respective values for Ashkenazi Jews, Sephardi Jews and Arabs were 30.6, 15.8, and 14.3% (P>0.01, Ashkenazi Jews vs. Sephardi Jews and Arabs). DN had a lower 3.7% while TP had a higher 46.1% prevalence compared to the group as a whole (P>0.01). In general, the increased frequency of anti HCV antibodies was significantly correlated to the duration of dialysis and the number of blood transfusions administered. This, however, was not the case in the greater prevalence of HCV found in Ashkenazi Jews compared to Sephardi Jews and Arabs which was independent of the above factors and the mode of dialysis. Our results showing increased HCV seropositivity in Ashkenazi Jews compared to Sephardi Jews and Arabs, suggest that ethnic factors might predispose to HCV transmission and infectivity.