For chronic hepatitis C virus (HCV) infection, the effects of current therapies are limited. To evaluate the efficacy and safety of the interferon beta-1a (IFN beta-1a) versus IFN beta-1a plus ribavirin (RBV) combination on Chinese treatment-naïve patients with chronic hepatitis C, a randomized, placebo-controlled study was performed. A total of 26 naïve patients histologically confirmed to have chronic hepatitis C were double-blindly and randomly assigned to receive either IFN beta-1a 44 microg (12 MIU) (IFN beta-1a group) or placebo (placebo group) three times per week for 12 weeks. At the end of the 12 weeks of treatment, the patients who received IFN beta-1a continued to complete 24 weeks of treatment. Placebo non-responders were crossed over to IFN beta-1a plus RBV (1,000-1,200 mg/day) combination therapy (IFN beta-1a plus RBV group) for 24 weeks after 4 weeks washout. All patients were followed up for 24 weeks after the end of treatment. Sustained virological response (SVR) was defined as the absence of detectable HCV RNA in the serum both at the end of 24 weeks of treatment and at the end of 24 weeks of untreated follow-up. There were no differences in the clinical background between the groups before the initiation of treatment. At the end of the 12 weeks of double-blind therapy, HCV RNA was negative and undetectable in 10/11 patients (90.9%) in the IFN beta-1a group and none in the placebo group. The virological response rate (14/15, 93.3%) of the IFN beta-1a plus RBV group at week 12 after the initiation of therapy was similar to that of the IFN beta-1a group. SVR was observed in 5/11 (45.5%) of the IFN beta-1a group and 11/15 (73.3%) of the IFN beta-1a plus RBV group (P = 0.23). At the end of follow-up, a biochemical response was found in 5/11 patients in the IFN beta-1a group (45.5%) and 8/15 patients in the IFN beta-1a plus RBV group (53.3%, P = 1.00). Multiple logistic regression analysis confirmed that an HCV RNA load lower than 1.0x10(6) copies/ml was independently associated with SVR (OR 11.00; 95% CI 1.81-66.97; P = 0.003). The side effects were mild and similar in the two therapy groups. We conclude that IFN beta-1a alone or in combination with RBV provided considerable benefit in Chinese naïve patients with chronic hepatitis C. Treatments with IFN beta-1a alone or IFN beta-1a plus RBV are safe and well tolerated, and may represent an alternative for chronic hepatitis C patients who are unable to tolerate pegylated interferon alpha.