Inclusion Criteria

• Hemophilia A or B
• Exposure to blood or blood products prior to 1987
• Participating in "The Second Multicenter Hemophilia Cohort Study (MHCS-II)"
• HCV reactive by second/third generation ELISA assay and/or RIBA
• HCV RNA positive (PCR or bDNA methods)
• Chronic hepatitis confirmed by liver biopsy within 6 months prior to study entry (Note: cirrhosis is not an exclusion factor)
• HIV infection for coinfected group; HIV viral load of 10,000 copies/ml or less
• If on antiretroviral drugs, stable regimen for at least 8 weeks prior to study entry
• Acceptable methods of contraception

Exclusion Criteria

• Hemoglobin less than 10 g/dl
• For HIV coinfected group, CD4 count less than 200 cells/mm3 at time of screening visit
• Previous interferon or ribavirin therapy
• Corticosteroids or immunomodulatory drugs within 3 months prior to study entry
• Hepatitis B (HBsAg reactive)
• Alpha-1 antitrypsin deficiency
• Wilson's disease
• Hemochromatosis
• Autoimmune disorder
• Decompensated liver disease evidenced by encephalopathy, ascites, or variceal bleed
• Prothrombin Time greater than 3 seconds above normal (International Normalized Ratio [INR] greater than 1.3)
• Platelet count less than 90,000/microL
• Active thyroid disease (thyroid replacement with normal TSH permitted)
• Chronic renal insufficiency, defined as creatinine greater than 1.5 mg/dl
• Life-threatening disease processes that could preclude completion of trial
• Alcohol abuse that the local investigator feels would interfere with compliance
• Illicit recreational drug use or methadone use within 6 months of study entry
• Major depression with hospitalization or suicide attempt is a relative, but not absolute, contraindication to therapy based on timing, circumstances, and current stability as assessed by the investigator
• Pregnant or breastfeeding