Background <p>Breast milk may have protective effects against autoimmune diseases because it contains components that support the immune system. This study aimed to evaluate the effect of breast milk intake during infancy on the clinical course and demographic characteristics of multiple sclerosis (MS) patients.</p> Methods <p>This study was designed as a cross-sectional study in MS patients. Sociodemographic data, duration and causes of breast milk intake, childhood diseases, nutritional habits, medication use, additional diseases, and Expanded Disability Status Scale (EDSS) scores of the patients were recorded through face-to-face interviews. The data were analyzed with SPSS program, and <i>p</i> &lt; 0.05 was considered statistically significant.</p> Results <p>Of the 105 patients participating in the study, 70% were female and 30% were male, with a mean age of 38.7 ± 10.4 years. 58% (61 individuals) of the participants had been breastfed for more than 12 months. These patients had a higher age of MS onset (<i>p</i> = 0.03) and lower EDSS scores (<i>p</i> = 0.04). Also, in the regression model, a one-unit increase in breastfeeding duration decreased the EDSS score by 0.487 points (<i>p</i> &lt; 0.05). However, no significant association was found between breastfeeding duration and relapse frequency or clinical course.</p> Conclusion <p>It was observed that long-term breastfeeding may delay the age of onset and slow down the disease progression in MS patients. However, the relatively small sample size, cross-sectional design, and potential recall bias may limit the generalizability of the findings. More comprehensive and long-term studies may reveal the importance of breastfeeding in MS more clearly.</p>