OBJECTIVE: To carry out a cost-utility analysis of the treatment of relapsing-remitting multiple sclerosis (RRMS) with glatiramer acetate (Copaxone) or interferon beta products (all as a whole, Avonex, Rebif and Betaferon). METHODS: Markov pharmacoeconomic model that compared treatments by simulating the life of a hypothetical cohort of 30 year old women, from the societal perspective. Transition probabilities, utilities, resource utilization and costs (direct and indirect) were estimated from Spanish sources and bibliography. Simple univariate sensitivity analyses of the base case were performed. RESULTS: In the base case analysis, the average cost per patient (€ in 2001) of life treatment, considering a life expectancy of 53 years, would be 1,243,906 euros (€), 1,818,149€, 1,763,263€, 1,987,153€ and 1,704,031€ with Copaxone, all the interferons, Avonex, Rebif and Betaferon, respectively. Thus, the savings with Copaxone would range from 460,000 to 737,000€ approximately. The quality-adjusted life years (QALY) obtained with Copaxone or the interferons would be 10.977 and 6.917, respectively, with a mean gain of 4.060 QALY/patient with Copaxone. Sensitivity analyses confirmed the robustness of the base case. Interferons would be superior to Copaxone only in the hypothetical and unlikely case that they delay the progression of the illness by 20% more than that presently observed in the clinical trials. CONCLUSIONS: For a typical patient with RRMS, treatment with Copaxone would be more efficient than interferons, which would be dominated by the former (Copaxone would be more effective with lower costs than the latter).