As part of a major health care reform starting in 2005, the Netherlands introduced a Diagnosis-Related Group (DRG) system of hospital care reimbursement and performance measurement. The DRG system was applied to all hospital care, meaning that it affected the overwhelming majority of Dutch specialist medical professionals. To better understand the consequences of this new system, and the responses of medical professionals to its implementation, we conducted and analysed an original set of sixty-six semi-structured interviews focused on medical specialists’ perception and utilization of the system. Our findings indicate that these professionals’ behaviours can seldom be ascribed to financial motives alone. Many responses of medical professionals to the new system were attributed to value-based motivations, related to upholding professional ethos and accommodating the dynamics of the professional process. Even responses that might be characterized at first as financially driven could not be entirely understood as perverse effects of the performance management system, as they too usually had an ancillary aim of safeguarding the professional tenets of the medical establishment.