Background: Metabolic syndrome (MS) has become a serious health problem worldwide and it is a major cause of morbidity and mortality especially from cardiovascular diseases. Different factors involved in pathogenesis like environmental, genetic, and sedentary life. Recent studies demonstrates that Vitamin D3 deficiency has a growing role in pathogenesis of MS. Many studies had addressed the relationship between serum Vitamin D3 and metabolic syndrome but to the best of our knowledge, few studies about this relationship in Egyptian population. Aims:To assess the relationship between deficiency of Vitamin D3 with metabolic syndrome in Egyptian population.Patients and methods: This is cross sectional study invite 200 participants from healthy clubs but only 180 accept to participate. According to the presence or absence of metabolic syndrome, our participant were divided into two groups. All participants were subjected to detailed medical history, clinical and anthropometric assessment, and laboratory analysis including serum Vitamin D3 level. Result:The mean age of the studied patients was 40.91±8.72, and majority were female (66.7%). Metabolic syndrome cases were significantly higher as regard the age, SBP, DBP, TG, FBS, WC and BMI but significantly lower regard HDL and Vitamin D3, and no significant association with sex. Vitamin D deficiency cases were significantly higher as regard Age, SBP, DBP, TG, FBS, WC and BMI but sig lower regard HDL. There was significant different between patients with and without Vitamin D3 deficiency as regard the presence of metabolic syndrome (P value=.00). There was moderate negative correlation between Vitamin D3 deficiency and age, SBP, DBP, FBS, WC and BMI with positive weak correlation with HDL level. Vitamin D3 deficiency < 20ng/ml and BMI >35 were significant predictors for metabolic syndrome with (P value 0.00, 0.04) respectively. Conclusion:Vitamin D3 level inversely correlates with the presence of metabolic syndrome in Egyptian