In order to clear some aspects of HCV infection, we evaluated quarterly HCV markers by a RIBA 1 test (antigens cl00-3 and 5.1.1) and monthly transaminases (ALT and AST) for 14 months in 89 HBsAg-free maintenance hemodialysis patients (MHP), and we retrospectively examined clinical records until the start of hemodialysis treatment. At the start of the study, 16 patients showed HCV antibodies (HCV +) and 73 were antibody-free (HCV-). 39 subjects of the staff were also examined. No HCV+ patient showed seroconversion, 10 showed irregular or persistent elevation of AST and ALT. In the retrospective evaluation 14 patients suffered from acute hepatitis (AH). Only 3 cases showed temporal relation with blood transfusions. In 1 case a 36-month temporary normalization of transaminases was noticed. 3 HCV- patients showed seroconversion (1 during AH), 13 showed severe or moderate elevations of transaminases. In the retrospective evaluation, 6 patients suffered from AH. All subjects of the staff were HCV-and showed no seroconversion or changes of transaminases. At the end of the study, we performed a RIBA 2 test containing the HCV antigens c100-3, 5.1.1, c22-3 and c33c. The 6 patients who suffered from AH showed at least 1 positivity for new proteins. Most of AH in MHP are likely due to HCV infection; besides transfusions, cross-infection during the dialytic procedure may be responsible for many cases of HCV infection; long-term normalization of transaminases may not secure against infectivity.