This article contributes to the continuing debate on the professional dominance of medicine given the rising number of professions allied to medicine that now have the legal authority to prescribe and could potentially threaten this dominance. The key questions addressed are whether non-medical prescribers represent a threat to the dominance of medicine and if they do not, what has mediated doctors' response to these newer prescribers such that they are able to retain dominance? Drawing on Abbott's work on jurisdictional claims, this paper explores how the rise of non-medical prescribing has led to competing jurisdictional claims over prescribing between doctors and non-medical prescribers. This paper particularly focuses on pharmacist prescribing and how competing jurisdictional claims could be settled. It discusses why the profession of medicine is still dominant and the importance of professional ideologies to influencing the outcome of competing jurisdictional claims. The professional ideology of medicine has shifted from valuing prescribing to valuing the indeterminacy involved in complex clinical decision making, illustrating medicine's ability to adapt, retain dominance and maintain cultural authority over clinical knowledge. In contrast, pharmacist prescribers' professional ideology involves having specialist medicines expertise and being safe prescribers. Pharmacists draw upon this ideology to argue their unique competence as a prescriber: given their pharmacological knowledge and attention to detail which facilitates their role as clinical checker or 'safety net' on prescribing. However, medicine's cultural authority in clinical decision-making enables, when there are competing jurisdictional claims over prescribing, for doctors to retain intellectual jurisdiction: control over the cognitive knowledge base involved in prescribing and clinical decision making. Could this be eroded to a weaker form of control involving advisory jurisdiction? Should political developments further favour the widespread acceptance of prescribing as a core part of the pharmacist's role, an erosion to advisory jurisdiction may yet be possible.