By examining the introduction and dissemination of external peer review through site-visits (visitatie) amongst Dutch medical specialists, this paper sets out to deepen our insight into the dynamics of professional self-regulation and health care policy making. We explore how visitatie has been used in the political process between medical specialists and the state, serving as a strategy in protecting the autonomy of physicians. In the late eighties and early nineties, factors both internal as well as external to the medical profession all together determined the start and spread of visitatie. The conflict between state and doctors over the specialists' income, the introduction of the market oriented policies, new visions on quality assurance, the debate on the future of medical specialistic care and a new legal framework on quality assurance, challenged the medical community to find ways to reconfirm the public's trust in the self-regulating mechanism of the profession. One answer is found in carrying out 300-400 visitaties annually. During the past years, many stakeholders have perceived visitatie as a credible instrument in assuring quality patient care. The dynamics of professionalization and measurable impact of visitatie will determine whether or not it is here to stay.