The purpose of the study is to assess the relationship between the prevalence of metabolic syndrome–related risk factors and work tenure among office workers. A 10-year cohort analysis was conducted using employees’ health examinations given to new employees within 1 or 2 years of joining the firm and every 5 years thereafter. Age-adjusted odds ratios (95% confidence interval [CI], p < .05) were calculated based on a contrast test with general estimating equations. Specifically, the age-adjusted odds ratios and CIs of those with 20 ± 1 years of work, compared with those with 1 to 2 years of work, were as follows: triglycerides (≥150 mg/dl) 3.01 (2.11, 4.28), waist circumference (male ≥90 cm) 2.70 (1.63, 4.45), and fasting glucose (≥100 mg/dl) 2.67 (1.78, 4.01). The findings of the relationship between metabolic syndrome risk and work tenure as well as the baseline health data of new employees provide a foundation for developing a workplace health management system.