Background: Multiple sclerosis (MS) is a chronic inflammatory, autoimmune, and neurodegenerative disease of the central nervous system. Our study aimed to examine the relationship between serum iron levels and the following clinical parameters: depression, anxiety, fatigue, neuropathic pain, and disease activity on magnetic resonance imaging in patients with relapsing-remitting multiple sclerosis (RRMS). Material and methods: This study was designed as a clinical observational, cross-sectional study. This study was conducted at the Clinic of Neurology of the University Clinical Center Kragujevac, from 2022 to 2024, according to the ethical code of the Declaration of Helsinki. Demographic and clinical data on patients were obtained from the medical history. All MS patients were diagnosed according to the McDonald criteria (2017). This study included 65 patients in the experimental group and 11 healthy individuals in the control group, with an average age of 39.68 years. Serum iron levels were biochemically analyzed from venous blood. The following standardized tests were used to collect data on depression, anxiety, fatigue, and neuropathic pain: Beck Depression Inventory (BDI), Hamilton Anxiety Rating Scale (HAM-A), Modified Fatigue Impact Scale (MFIS), PainDETECT Questionnaire (PD-Q), and Visual Analogue Scale (VAS). Results: Serum iron level significantly correlates with disease activity on magnetic resonance imaging in patients with multiple sclerosis. Serum iron showed a moderate positive correlation with hemoglobin, hematocrit, total and direct bilirubin, and a weak positive correlation with uric acid, while a moderate negative correlation was observed with erythrocyte sedimentation rate. No statistically significant difference was found between serum iron levels and depression, anxiety, fatigue, and severity of neuropathic pain. The ROC curves show the diagnostic potential of the combined parameters in differentiating RRMS from controls, as well as the potential of iron in differentiating active from inactive MS. The presence of disease, hemoglobin and total bilirubin were recorded as significant independent predictors. Conclusion: This study is a descriptive attempt to present the potential role of iron in the radiological activity of the disease. High serum iron level may be associated with radiological disease activity in patients with multiple sclerosis.