Multiple sclerosis (MS) is an autoimmune neurodegenerative disease that affects the central nervous system. It is the second cause of neurological disability in young adults. The exact cause of the disease remains unknown and there is no curative treatment. It is imperative to evaluate the efficacy of newest, biotechnological products modifying the disease. This study was designed to evaluate the use of interferon beta 1a (Rebif®) in patients with relapsing remitting MS treated at International Center for Neurological Restoration. Thirty‐one patients with relapsing remitting MS, between 10 and 65 years of age, four males and 27 females, were treated with Rebif® three times per week during 1 year. The safety of the treatment was evaluated based on the adverse events and the efficacy based on the disability scale score, the number of attacks and the number of lesions at magnetic resonance imaging (MRI). The public clinical trial is registered in Cuba (Number B‐10‐030‐L03). Adverse effects occurred in 75% of the cases, but they were mild. A significant reduction in the number of attacks, the disability scale score and the number of lesions at MRI were observed in patients with relapsing remitting MS treated with Rebif®. The use of interferon beta 1a showed safety and efficacy in the treatment of patients with relapsing remitting MS.