Objectives: Commercialization of occupational health services (OHS) and transition to a supplier market which started in 1995, has affected work and working conditions of occupational physicians (OPs) profoundly. OPs have lost influence on the organization of their work and managers took over control. This study explores the impact of commercialization on job satisfaction of occupational physicians. Material and Methods: Data were collected through a questionnaire completed by 797 OPs, members of the Netherlands Association of Occupational Medicine (response: 45%). A range of work satisfiers and dissatisfiers measures was included that, according to the Social Action Approach, could explain the variation in job satisfaction. Stepwise multivariate regression analyses were performed to explore to what extent the differences in job satisfaction can be attributed to the characteristics of the setting, biographical variables, satisfiers and dissatisfiers. Results: Occupational physicians in commercial settings had the lowest average score as regards job satisfaction (6.7) contrasting sharply with their colleagues in private practices (8.7) and in non-commercial settings (7.9). The variation in job satisfaction between delivery settings could largely be attributed to satisfiers and dissatisfiers. Biographical characteristics (age, gender) had no effect. The data suggested that not commercialization as such, but the ability of commercial OHS providers to integrate professional values was the crucial factor to bring about job satisfaction. Conclusions: The challenge for commercial OHS providers is to preserve the professional zeal in OPs by integrating professional values in their organization in order to improve the quality of the services and the attractiveness of the profession.