As we are entering an era where intelligent systems are omnipresent and where they also penetrate Prognostics and Health Management (PHM), the discussion of moral machines or ethics in engineering will inevitably engulf PHM as well. This article explores the topic of ethics within the PHM domain: how it is relevant, and how it may be dealt with in a conscientious way. The paper provides a historical perspective on ethics-related developments that resulted in the formulation of engineering ethics codes, regulations, and policies. By virtue of these developments, ethics has already been encapsulated in PHM systems. The specific areas that have traditionally driven ethics considerations include safety and security, and they increasingly include privacy, and environmental protection. During the course of future technology development, innovations will increasingly impact all of these topics. It is argued that consciously embracing these issues will increase the competitive advantage of a PHM technology solution. As a guideline, specific ethics attributes are derived from professional engineering ethics codes, and a path towards insertion into a requirements flowdown is suggested.