- The prevalence of hepatitis C virus (HCV)-RNA positivity among hemodialysis patients varies between 10 and 70%. Few previous surveys revealed high frequency of seroconversion of HCV-RNA-negative patients over the years of hemodialysis. Only few studies reported HCV genotype variability. We evaluated all 65 patients on chronic hemodialysis in our dialysis unit. All sera positive to anti-HCV on ELISA were retested by reverse transcriptase polymerase chain reaction to HCV-RNA. Sixteen patients were found anti-HCV positive on ELISA, and 8 of them were also PCR positive. Three of these eight patients seroconverted during the year 1995. Four patients had both 1a and 1b genotypes of HCV, coexistence of genotypes 1b and 4a in one patient and genotypes 1a, 1b and 2a in the remaining three patients. Mean serum aminotransferase, duration of dialysis, and number of blood units transfused were significantly higher in the HCV-PCR-positive patients compared with the HCV-PCR-negative patients. Because strict isolation methods were initiated at the end of 1995, not one new case of HCV among dialysis patients was found in 1998, although new hemodialysis patients were diagnosed as having HCV. In conclusion, genotypes 1a and 1b, as is true for the general population in Israel, were also the predominant genotypes among hemodialysis patients; the coexistence of more than one genotype is common among hemodialysis patients; seroconversion is common among these patients and strict isolation methods are efficient and should be recommended.