Does the increasing importance of guidelines in health care threaten the professional status of health care professions by reducing their professional autonomy? Or does it increase their position through enhancing their scientific status? In this paper, we focus on this apparent contradiction by studying how Dutch insurance physicians created and used guidelines for the evaluation of labour disability claims. Drawing upon the theoretical repertoire of science and technology studies, we studied the role of the notion of 'objectivity' in these developments. A specific redefinition of objectivity played a core role in the active alignment, by the insurance physicians' profession, of the processes of guideline development and professionalisation. Simultaneously, it is argued, a specific conceptualisation of the position of the client was put to the fore. Guidelines, it seems, can be drawn upon creatively so that rather than embodying a potential constant threat to professional autonomy, they actually enforce it.