BACKGROUND: Hepatitis C virus (HCV) has been identified as one of the most frequent causative agent of posttransplant non-A, non-B hepatitis, but the significance of anti-HCV antibodies after transplantation remains controversial. In the present study, we performed anti-HCV and HCV-RNA RT-PCR (HCV PCR) in the kidney recipients to assess the incidence and the outcome of HCV markers after transplantation. MATERIALS AND METHODS: In randomly selected 95 patients' paired sera (before and after transplant samples, respectively), we performed anti-HCV test by Abbott HCV EIA 3.0. We also performed HCV PCR in 80 paired sera of the 95 patients. We evaluated the incidence of anti-HCV and HCV PCR and compared the results in the kidney recipients between anti-HCV test and HCV PCR before and after transplantation. RESULTS: In the recipients' sera before transplantation, 16 (16.8%) among 95 sera were anti-HCV positive and 27 (33.8%) among 80 sera were HCV RNA positive. Among the 80 pretransplant sera performed HCV PCR, 23 (28.8%) discordant results were noted between anti-HCV and HCV PCR, and 17 sera among these were HCV PCR positive and anti-HCV negative. A seroconversion from anti-HCV negative to positive after transplantation was observed in 10 sera, but a conversion from positive to negative was not observed. In case of HCV PCR, a conversion from negative to positive was observed in 21 paired sera, and positive to negative in 13 paired sera. CONCLUSIONS: Our study indicated that disapperance of anti-HCV antibodies after transplantation in kidney recipients was rare. The overall concordance rates between anti-HCV test and HCV PCR in the recipients before and after renal transplantation were lower than other non-transplanted groups reported, and it may be due to the immunosuppressive therapy or the changes in immunoregulatory function of the patients. Further study such as follow-up liver function tests or liver biopsy will be needed for accurate decision about posttransplant HCV status of kidney recipients.