This study examined the influence of ribavirin on the initial virological response in treatment-naïve participants with chronic hepatitis C, genotype 1. Participants were randomized to 1 of 3 treatment groups to receive placebo, ribavirin monotherapy 1000 milligrams (mg) to 1200 mg orally daily depending on body weight or pegylated interferon (PEG-IFN) alfa-2a (Pegasys®) 180 micrograms (mcg) subcutaneously (SC) weekly, for 6 weeks. Following the initial 6 weeks, all participants received combination therapy with PEG-IFN alfa-2a plus ribavirin (Copegus®) for 12 weeks. If there was an initial virological response after 12 weeks of combination therapy, treatment could be continued for a further 36 weeks outside of the study.