Purpose – This study aims to examine the role of instrumental vs intrinsic work orientations in the job demands-resources (JD-R) model. Design/methodology – Using a sample of 123 employees, the authors investigated longitudinally whether an instrumental work orientation moderates the motivational process, and mediates the health impairment process in the JD-R model. Findings – Regression analyses revealed that an increase in job resources over time was particularly beneficial for experienced flow at Time 2 among employees holding an instrumental (vs intrinsic) work orientation. In addition, structural equation modeling analyses showed that work pressure was reciprocal with need for recovery, which was reciprocal with instrumental work orientation. Research limitations/implications – Findings suggest that work orientation should be integrated in research linking work characteristics with motivational and health impairment processes. Practical implications – Organizations should avoid placing overly high demands on their employees as these not only impair employees' health, but also change their orientation towards work. Social implications – Organizations can contribute to the wellbeing of individuals and society by designing jobs that provide affordable demands and sufficient resources. Originality/value – The present study successfully integrated work orientations in the JD-R model.