Abstract: Aim of the study is to investigate the correlations between serum concentrations of 25-hydroxyvitamin [25(OH)D] and components of metabolic syndrome in Egyptian men. Ninety-three Egyptian men with metabolic syndrome and seventy age matched healthy males were included in this study. Metabolic syndrome was diagnosed based on modified International Diabetes Federation worldwide definition of the metabolic syndrome (MetS), using Body Mass Index (BMI) instead of waist circumference. We found that serum 25(OH) D levels were significantly lower in the MetS patients than control subjects. In MetS patients, serum 25(OH)D levels were significantly correlated with BMI, insulin, HOMA, HDL and PTH. After splitting of the serum 25(OH)D into 4 quartiles, with lowest one < 25 nmol L-1 (presumed hypovitaminosis D as the new reference category ). In the first quartile, we found that 25(OH)D levels were significantly correlated with BMI, SBP, DBP, FBS, insulin, HOMA,TG and HDL. In the 2nd quartile, 25(OH)D levels were significantly correlated with BMI, insulin, HOMA and HDL. While in the third and fourth quartiles, 25(OH)D levels were significantly correlated with only HDL component of metabolic syndrome. So the patients with the lowest serum 25(OH)D levels have the more significant correlation with the MetS components as well as insulin levels and HOMA. In addition, the 25(OH)D levels were correlated significantly with serum PTH levels all through in the 4 quartiles. In conclusion, our study showed a correlation between low serum vitamin D and different components of metabolic syndrome in Egyptian men. Hypovitaminosis D should be considered as a risk factor for the metabolic syndrome.