Professionals in the field of radiological protection from sources of ionising radiation are subject to various codes of ethics published by the professional organisations and associations representing the community of radiological scientists and practitioners. The community and its individual members accept the codes' terms and conditions, and understand the professional consequences of non-compliance. However, while these codes of ethics may be prescriptive with respect to the general understanding of 'ethical behaviour' or 'professional conduct' of radiological protection professionals, they often provide little guidance on an ethical decision making process when conflicting interests and intentions require professional judgment. Radiological protection professionals serve as contractors to clients or advisers to employers, but are also expected to actively contribute to the radiological protection community and emphasise the welfare of and benefit to the general public. This paper summarises the philosophical approach to an ethical decision making process and attempts to clarify the role of the 'professional' in that process. It investigates the responsibilities, duties, and virtues of a radiological protection professional and explains the ethically prescribed position for the professional in the decision making process. Radiological protection professionals may not have the authority to render a binding decision, but their most ethical conduct may actually be in their intimate involvement in the development and execution of the final 'ethical decision' by providing guidance and counsel to the decision maker in a fiduciary professional-client relationship. The main pillars of a trusting professional-client relationship are the professional's integrity and communication skills.