Abstract Objective: Knowledge about bidirectional microbiome-gut-brain interactions has gradually increased in multiple sclerosis (MS) and many other diseases. The aim of this study is to determine the prevalence of irritable bowel syndrome (IBS) in MS patients, to compare with a control group and to identify the relationship between MS attacks and gastrointestinal (GI) symptoms. Methods: Patients with at least a two-year diagnosis of relapsing-remitting MS (RRMS) from our outpatient clinic were included in the study. The duration of disease, expanded disability status scale and time of MS attacks were recorded. ROME- IV criteria were used for diagnosis of IBS. Results were compared with the control group. IBS symptoms prior to, during and after an attack were recorded and their relationship to MS attacks was investigated. Results: 93 RRMS patients and 101 controls were included in this study. The prevalence rate of IBS was found to be 16.1% (n=15) in MS patients and 8.9% (n=9) in the control group. No significant difference can be found in IBS prevalence rate between MS patients and controls (p=0.127). MS attacks had no significant effect on constipation, diarrhea, abdominal pain and distention. Conclusion: This study showed that MS patients have a similar IBS prevalence to the control group. In addition, MS attacks have no significant effect on GI symptoms.