This study has been designed as an observational, hypothesis-generating pilot study of patients with chronic hepatitis C requiring organ transplantation and concomitant immunosuppression. Patients who require a liver-transplant for chronic hepatitis C-related end-stage liver disease and patients with hepatitis C who require a kidney transplant for renal failure will be enrolled and followed for up to five years. Virologic, immunologic and intrahepatic parameters will be correlated with the level of immunosuppression, degree of fibrosis, progression to cirrhosis and liver-related deaths in study subjects. The objectives of this study are to: 1) determine the proportion of patients with hepatitis C that progress to bridging fibrosis or cirrhosis at three and five years after liver or kidney transplantation (rapid-progressors); 2) compare virologic, host-immune and intrahepatic factors in rapid-progressors to non-progressors and slow progressors; 3) characterize the relationship between general and HCV-specific immune responses and the extent of liver fibrosis; and 4) develop a predictive model that discriminates between rapid-progressors and non- or slow-progressors.