The recent decline in professionalism has frequently been explained as a result of the rise of New Public Management (NPM). As will be shown in this article, however, NPM does not automatically result in a decline in professionalism; its effects differ in various professional contexts. In a case study of the work of social insurance doctors and labor specialists the authors demonstrate that NPM structures the technical aspects of professional tasks, that are the verifiable elements of the professional's judgment. NPM proofs to have strong influence on the techniques for quality insurance (performance of production, time and lawfulness). On the longer term this influence can undermine professional self-regulation. NPM has little impact on the indeterminate task aspects, the professional judgment itself, even though this part has become more 'technical' in years. The case study shows however that this is not due to NPM but to the impact of bureaucratization of the professional task. Furthermore it becomes clear that this impact is stronger in the case of the labor specialist than with respect to the social insurance doctor.