Using the ELISA method (generation II), the authors made a single examination of 172 dialyzed patients for the presence of antibodies against the virus of hepatitis C (VHC). Antibodies were detected in 82 subjects, i. e. 47.7%. The prevalence of antibodies in the examined subjects increased with the number of dialyses, no relationship was found with the number of transfusions. Of 104 subjects where during inclusion into the dialyzation transplantation programme a rise of ALT occurred 69, i. e. 66.3%, had antibodies. Antibodies were detected in 17 of 44 subjects (38.6%) to whom so far blood was not administered. A decisive place in the prevention of VHC transmission in dialyzed subjects is held by non-specific preventive measures, transfusions are most probably not the decisive vehicle.