This observational study will evaluate the predictive value of rapid virological response (RVR) and early virological response (EVR) on sustained virological response (SVR) by stage of liver fibrosis in treatment-naïve patients with chronic hepatitis C genotype 1 initiated on treatment with Pegasys (peginterferon alfa-2a) and Copegus (ribavirin). Patients will be followed for 48 weeks of treatment and up to 24 weeks of follow-up.

Inclusion Criteria:

• Adult patients, >/= 18 years of age
• Chronic hepatitis C genotype 1
• Treatment-naïve, i.e. have not been previously treated with pegylated interferon, standard interferon and ribavirin
• Confirmed serum positive HCV RNA
• Liver fibrosis confirmed histologically or by fibroscan up to 24 months before treatment

Exclusion Criteria:

• Any contraindications according to the Summary of Product Characteristics for Pegasys or Copegus
• Co-infection with hepatitis B or HIV
• Post-transplant patients
• End stage renal disease (creatinine clearance < 15 ml/min)
• Patients treated with immunotherapy
• Pregnant women and male partners of women who are pregnant
• Female patients of childbearing potential and male patients with female partners of childbearing potential who are unable or unwilling to use effective and continuous contraception during the treatment and for 4 months (females) and 7 months (males) thereafter

Treatment-naïve patients with chronic hepatitis C genotype 1 initiated on treatment with Pegasys and Copegus