Chronic hepatitis C virus (HCV) infection is the first cause of liver disease after renal transplantation. The prevalence of HCV infection in dialysis and in renal-transplant patients remains high. Mortality of HCV-positive renal-transplant patients is higher than that of HCV-negative ones. Liver disease and sepsis seem to be the main causes of death. Graft survival is also lower in HCV-positive renal-transplant patients. This seems to be due in part to the occurrence of de novo glomerulopathy. The effect of HCV infection upon liver fibrosis in renal-transplant patients receiving immunosuppressive treatment remains controversial. To date, there is no efficient treatment of HCV infection after renal transplantation. Consequently, it is mandatory to treat by alpha-interferon all HCV-positive/RNA-positive dialysis patients waiting for renal transplantation.