Background and purpose: Metabolic syndrome reduces the quality of life and cognitive function. The health of railway staff is of great importance as proper health status could increase the quality of rail services delivered. Therefore, this study was performed to assess the quality of life of railway employees according to being affected by metabolic syndrome or not. Materials and methods:This cross-sectional study was performed in 409 employees of the railway services attending an occupational health clinic for annual examination in Mashhad, Iran. Demographic characteristics were recorded and body mass index, blood pressure, and waist circumference were measured. The levels of FBS, HDL, LDL, and triglycerides were also evaluated. Metabolic syndrome was defined according to NCEP ATP III criteria. Finally, the quality of life score wascompared between people with/without metabolic syndrome based on the WHOQOL-BREF questionnaire. Results:The mean age of participants was 38.65 ± 6.4 years. Work experience and BMI were significantly higher in staff with metabolic syndrome (P= 0.0005 and P< 0.001, respectively). The mean scores for physical health (11.36±1.47) and social relations were found to be significantly higher in participants without metabolic syndrome (P<0.001 and P= 0.001, respectively). The mean score for mentalhealth in people with metabolic syndrome was significantly higher than the other group (P= 0.02). The meanscore for environmental health did not show any significant differences between the two groups (P= 0.31). Conclusion:Metabolic syndrome can affect the quality of life of employees, including their physical, mental and social health.