- Patients will be recruited from the Pittsburgh AIDS Center for Treatment (PACT) Clinic and Pitt Treatment and Evaluation Unit (PTEU) and the Center for Liver Diseases (CLD) at the University of Pittsburgh. There are approximately 800 patients in the University of Pittsburgh's PACT/PTEU clinic. Consecutive patients with HCV-HIV co-infection who present to the clinic upon initiation of data gathering would be eligible for participation in this study. An estimated 500-800 patients are seen at the CLD clinic per year, and consecutive patients enrolled in the CLD HCV registry would be considered eligible for this study. To maintain uniformity and consistency of data, only patients seen by one of the study investigators would be enrolled. Recruitment would continue till the study has enrolled 100 HCV-HIV coinfected and 200 HCV mono-infected subjects.