Introduction. Metabolic syndrome is an important medical and epidemiologic entity, Currently, there is sufficient evidence to suggest a Metabolic syndrome-male infertility paradigmAim. To clarify the correlation between Metabolic syndrome and male factor infertility ,showing its effect on seminal parameters.Methods. The study was performed on 200 males, who were recruited from the outpatient clinic of Andrology and Diabetes, Cairo university hospital.100 of them had features of Metabolic syndrome according to the IDF definition and 100 not fulfilling the definition. History was taken, general and local examination applied, lipid profile and FBS measured and semen samples were analyzed according to the World Health Organization 2010 guidelines by using CASA apparatus.Results. Males with Metabolic syndrome had poor semen quality regarding all seminal parameters as volume , sperm concentration, total motility, progressive motility and abnormal forms with a mean and standard deviation of 2.7±0.7 , 18.3±13.4 , 30.7±12.5 , 20.9±10 , 71.7±14.5 respectively, with a significant difference compared to control group ( p value <0.001).Among criteria of Metabolic syndrome : WC , FBS and HDL were found to affect semen more significantly than HTN and triglycrides.Increased number of Metabolic syndrome components above 3 components is not associated with increased affection of seminal parameters.Conclusion. Metabolic syndrome is associated with poor semen quality & severity of Metabolic syndrome is not associated with increased affection of seminal parameters.