the purpose of our study is to evaluate the efficacy of azathioprine as first-line treatment in patients with relapsing-remitting multiple sclerosis (RRMS) or progressive multiple sclerosis (PMS), who were supposed to be treated with beta-interferons but, due to limited resources, received azathioprine instead. among the 31 patients, 17 had relapsing-remitting MS (RRMS), 11 had primary progressive MS (PPMS), and 3 had secondary progressive MS (SPMS). Patients received azathioprine orally at a dose of 3 mg/kg/day over 2 years. The effect of azathioprine was assessed using the Expanded Disability Status Scale (EDSS) score. Compare means t-test was used to determine the treatment performance. for RRMS, the mean EDSS score ranged between 4.2 and 3.6±1.4. A total of 82.4% of patients were stable or improved, with a very highly significant difference (P= 0.000). For PPMS, the mean EDSS score remained constant at 5.7 ±0.4. A total of 54.5% of patients showed stability or improvement, with a highly significant difference (P= 0.005). In the case of SPMS, the mean EDSS score ranged between 4.5 and 4.1±1.3. A total of 66.7% of patients were stable or improved but with a non-significant difference (P= 0.1). the results of this study confirm that azathioprine is beneficial in the treatment of different types of multiple sclerosis in Morocco.