The aim of this study was to evaluate the effect and maintenance of core stability exercises on electromyography activity in patients with multiple sclerosis. 24 patients with multiple sclerosis were randomly divided into experimental and control groups. The amount of muscle activity were assessed using electromyography during the descent from the platform in the pre-test, post-test, and follow-up. The experimental group performed the core exercises three times a week for eight weeks. Data were analyzed using analysis of variance with repeated and independent t-test and repeated measures ANOVA and Bonferroni post hoc test at a significance level of 0.05. The results showed that core stability exercises led to a significant decrease in muscle activity from pre-test to post-test (p ≤0.05) but there was no significant difference between post-test and follow-up. The results also showed that a significant difference was observed in muscle activity between the experimental and control groups in the post-test and follow-up (p ≤0.05), while no significant difference was reported in muscle activity in the pre-test. In addition, no significant difference was observed for the control group in the pre-test, post-test, and follow-up. According to research findings, core stability exercises can be a factor in reducing muscle activity while descending stairs in patients with multiple sclerosis. In this way, relevant specialists can use these exercises as a supplement to drug treatments for these patients.