Low incidence rates of hepatocellular carcinoma and cirrhosis in HCV-antibody-positive patients on chronic hemodialysis are reported. Among the patients, two cases undergoing negative conversion of the anti-HCV-antibody were found. Considering the size of the virus particles and the pore size of the dialysis membrane, it seems the virus does not escape from the membrane pore. Indeed, virus particles may be trapped and destroyed at the membrane surface. The size of HCV-RNA titers in HCV-antibody-positive patients receiving various kinds of chronic blood purification procedures are of interest. The subjects included 15 hemodialysis patients, 10 hemofiltration patients, 9 continuous ambulatory peritoneal dialysis patients, 7 chronic renal failure predialysis patients, and 14 patients with excellent renal function. The concentration of HCV-RNA particles in patients receiving chronic hemofiltration was significantly lower than that in patients of other groups. Hemofiltration, which is routinely performed at over 150 mm Hg TMP, may be an important key to decreasing HCV-RNA particles by a mechanism such as destruction.