Objective: The primary objective of this study is to describe the disease characteristics of the cohort of MS patients undergoing Rebif treatment. Design:This is a multicentre, open label, non comparative, non randomized study conducted in Egypt on the use of interferon beta-1a (Rebif) therapy in Egyptian patients with relapsing multiple sclerosis according to McDonald criteria. Subjects: Egyptian patients with relapsing multiple sclerosis who are naïve to interferon and are 18 to 65 years old. Settings:A total number of 36 patients were enrolled. Main Outcome Measures:include the mean number of relapses, time from diagnosis to start of treatment, number of relapses prior to start of treatment, annualized relapse rate, incidence of adverse events associated with Rebif therapy and number and location of lesions in MRI. Results:7 patients were excluded from Intention-to-Treat Population as they were enrolled regardless of the inclusion/exclusion criteria. Therefore, the Per Protocol Population included 29 patients including 11 males and 18 females and with a mean age of 31.41 years old.  The number of reported relapses was 4.3 and 11 at visit 1, visit 2 and end of the study respectively. Despite this increase, only 13 out of 29 patients (44.83% - 95%CI: 28.4% to 62.4%) had relapse attacks during the study (48 weeks). The annualized relapse rate was 0.79 ± 0.41 (95% CI) relapse per year. 9 patients out of 36 patients (25% - 95%CI: 13.75 to 41.07%) in the safety population had adverse events during the study. 2 were reported at baseline, 5 at visit 1, 1 at visit two and 1 at visit 3. The adverse events were elevated liver enzymes (2), depression (2), injection site pain (1), allergic skin reaction (2) and flu like symptoms (1). Conclusion:Compared to previously reported results, this study indicates that Rebif appears to have a favorable efficacy profile as well as a favorable safety profile in delaying MS progression in Egyptian patients.