As a patient approaches the end of life, he or she faces a number of very difficult medical decisions. Allied health care professionals, including speech-language pathologists (SLPs) and occupational therapists (OTs), can be instrumental in assisting their patients to make advance care plans, although their traditional job descriptions do not include this role. The allied health care professional is often in a trusted position, permitting insight into the values and beliefs of the patient and facilitating the depth of communication necessary when making difficult decisions. Professionals who work with clients at the end of life need to be aware of the many issues surrounding end-of-life decision making and the preparation of advance directives for care. This article provides an overview of the complex issues the practicing clinician needs to keep in mind when assisting clients with advance care planning. This service requires that clinicians step outside their roles as rehabilitation experts, a move that is supported by professional associations. The concepts of medical decision making and informed consent are discussed in the context of decisions made in advance of illness at the end of life. The professional needs also to be aware of the legalities of advance decision making, as laws and statutes differ between states/provinces. There are overarching pieces of legislation that inform local legal and policy issues; the impact of these is briefly addressed. Various forms of documenting advance care plans, as well as their strengths and weaknesses, are discussed. Decision models are introduced as a means of guiding the clinician to provide quality care. Means of offering practical assistance to the client, such as motivational interviewing, the careful selection of appropriate educational material, and prevention of undue influence on the patient are discussed. Finally, the role of the allied health care professional in advocating for the client during the implementation is addressed. Understanding how the advance care plan should be implemented when a patient becomes incapable is essential when advocating for and protecting the rights of the patient. When a professional is prepared with the requisite understanding of all of the facets of advance care planning, he or she can become a strong ally for the patient and the family at this very important phase of life.