Objective: Multiple sclerosis (MS) is a chronic and progressive neurological disease affecting the central nervous system (CNS). Some studies report an association between MS pathogenesis and cytokines. Here, we aimed to determine and evaluate serum kisspeptin-10 level in MS patients and its related clinic parameters. Materials and Methods: A total of 92 participants, 46 patients with relapsing-remitting MS (mean age, 38.92 +- 14.76; 22 men and 24 women) and 46 healthy controls (mean age, 37.04 +- 15.49; 22 men and 24 women) were enrolled in the study. All MS patients were neurologically examined, and magnetic resonance imaging (MRI) was performed. Clinical data (neuropathic pain, expanded disability status scale (EDSS) score, etc.) and the patients? demographic characteristics were recorded. The serum level of kisspeptin10 was analyzed by enzyme-linked immunosorbent assay (ELISA) method. Results: The level of kisspeptin-10 was measured as 2.305 +- 2.781 ng/mL in MS patients and 9.342 +- 9.483 ng/mL in controls. MS patients had significantly lower kisspeptin-10 levels than controls (P 5 0.000). Kisspeptin-10 has the highest diagnostic value [Area under curve (AUC) 5 0.881, 95% confidence interval (CI), 0.812-0.950] as cut-off value (2.470), sensitivity (80.40%) and specificity (72.87%) in the MS group. Furthermore, the kisspeptin-10 level was negatively correlated with third ventricle diameter (TVD) (P 5 0.048) and vitamin D concentration (P 5 0.004). No significant difference was determined between kisspeptin-10 and other clinical parameters. Conclusion: As a potential prognostic biomarker, serum kisspeptin-10 level was significantly lower in patients with MS than in those without. Moreover, we observed negative correlations between vitamin D, TVD size, and kisspeptin-10. We think comprehensive studies are needed to verify and elucidate this issue.  Kulcsszavak.: kisspeptin-10, multiple sclerosis, neurological disease, third ventricle, vitamin D