Introduction: Familial Mediterranean Fever (FMF) is an autosomal recessive autoinflammatory disorder. Vitamin D deficiency is a common finding in patients with various chronic inflammatory diseases. Several studies have elucidated the correlation between serum vitamin D levels and disease activity in pediatric Familial Mediterranean Fever patients. In this study, we aimed to investigate the role of vitamin D in the development of Familial Mediterranean. Method: This study includes 95 pediatric patients diagnosed with Familial Mediterranean Fever who were followed by the Department of Pediatrics at an Application and Research Hospital in Turkey and agreed to participate in the study. Additionally, 34 healthy children who consented to participate constituted the control group. The diagnosis of patients with FMF utilized the Tel-Hashomer criteria Results: The hormone levels of FMF and control groups were compared. Vitamin D levels, calcium, phosphorus, Parathyroid Hormone and Alkaline Phosphatase levels were analyzed. In the FMF group, the Vitamin D level was found to be significantly lower, while the Ca and phosphorus levels were significantly higher compared to the control group (both with p<0.01). Although the difference in Ca levels between the two groups was statistically significant, the mean Ca levels of both groups remained within the normal range. Conclusion: In conclusion, the significant deficiency of serum vitamin D levels in pediatric FMF patients and its association with disease severity underscores the importance of regular monitoring and potential therapeutic intervention.