The aim of this study was the investigation of hepatitis C virus (HCV) RNA by reverse transcriptase-polymerase chain reaction (RT-PCR), in hemodialysis patients in order to detect HCV infection, and the determination of virus genotypes in HCV positive patients. A total of 94 patients, 44 female and 50 male (mean age: 49 +/- 17 years old), who were included in hemodialysis program between 1987-1999 (0-13 years) in the Hemodialysis Units of Gazi University, School of Medicine and Ankara Etlik Hospital of Social Insurance Society, were enrolled in the study. Anti-HCV was found positive in 41 patients (43.6%), while HCV-RNA was positive in 36 patients (38.3%). Thirty three of the patients were positive for both anti-HCV and HCV-RNA, 8 were anti-HCV positive HCV-RNA negative, and 3 were anti-HCV negative HCV-RNA positive. HCV was genotyped by Restriction Fragment Length Polymorphism (RFLP) method in 36 HCV-RNA positive patients, and 28 yielded genotype 1b, and 8 showed genotype 1a pattern. PCR products from 5'UTR of HCV-RNA isolated from two patients were also sequenced to confirm the results of RFLP study. The rate of anti-HCV and HCV-RNA positivity was detected statistically higher in patients who exposed hemodialysis longer than 24 months, and in hemodialysis patients who had blood transfusion than the other groups. As a result, our findings supported that the periodic follow-up of HCV-RNA, in addition to anti-HCV would be useful for hemodialysis patients, and genotyping of HCV for the epidemiologic data.