Background & Objective: No clinical study of any interferon beta therapy has yet been successfully conducted in Chinese multiple sclerosis patients, probably due to the low incidence of this disease in China. The primary objective of this study was to demonstrate that treating multiple sclerosis patients of Chinese origin with interferon beta-1b has a beneficial effect on disease course, as measured by the decrease of newly active lesions on magnetic resonance imaging. Methods: Chinese patients diagnosed with relapsing-remitting or secondary-progressive multiple sclerosis were enrolled in this multicenter, open label, single-arm study. Following a 3-month pre-treatment phase, patients were treated with 250 mu g interferon beta-1b subcutaneously every other day for 6 months. Patients had regular assessments for treatment safety and efficacy of the treatment. Results: Thirty seven patients completed the trial. Significant decreases in the number of newly active lesions were observed in the 6-month treatment period compared with the pre-treatment period (median decrease 1.5 lesions, p<0.001). Most adverse events were mild and transient and no serious ones were observed. Conclusions: Treatment with interferon beta-1b significantly reduced the occurrence of new lesions and was well tolerated in this Chinese population. These findings support the use of interferon beta-1b for treating Chinese MS patients.