Workplace is an ideal setting to target individuals that may not attended primary care services. Indeed, routine employees’ check-ups may facilitate screening programmes. The French National Railways Company (SNCF) conducted a workplace health promotion programme (2011-2015) for all its employees including an overweight screening. The aim of this work was to study the determinants of high blood pressure among overweight employees. Methods: Body mass index (BMI) was calculated for the 155 000 employees during their occupational health check-up. Employees with a BMI ≥25 kg/m2 were invited to a complementary screening. Overweight volunteers (n = 7724) were referred to a multidisciplinary intervention. A questionnaire on dietary, physical activity, sleeping behaviours, and working conditions, was administered. Multivariate logistic regression was used to identify predictors of high blood pressure. Results: Overall, 30.1% of overweight employees presented a high blood pressure. We focused our analysis on job position that translates a social gradient. Compared to employees with an intermediate job position, those with higher position were less likely to present high blood pressure (univariate OR = 0.7 [0.6-0.8]). Employees with lower job position were less likely to present high blood pressure compared to intermediate position employees (univariate OR = 0.8 [0.7-0.9]). In multivariate analysis, this association remained high and statistically significant for employees with higher job position (fully adjusted OR = 0.6 [0.5-0.8]). However, this association decreased and became non-significant for employees with lower job position compared with employees with intermediate job position (age adjusted OR = 1 (0.8-1.1]; fully adjusted OR = 1.1 [0.9-1.3]). Conclusions: High blood pressure was associated with job position with a U shaped phenomenon. Greater attention is needed to identify determinants of risk factors at work to target high risk populations and prevent chronic diseases.