A living will—also known as an Advance Health Care Directive—is a document in which the declarant or principal (person making the living will) specifies what kind of medical treatment the declarant does and does not want if the declarant has a medical emergency and is unable to communicate those wishes. A living will may direct health care providers to administer, withhold, or withdraw life-sustaining treatments if the declarant is in a terminal or irreversible condition.

Laws and terminology for documents related to living wills, Advance Health Care Directives, Do Not Resuscitate orders (DNRs), and other health care documents vary from state to state. These laws are generally located in a state’s statutes—often in the probate code or estates code.

In Arizona, a living will is recognized under state law as a legal document that allows an individual, known as the declarant, to outline their preferences for medical treatment in the event that they are unable to communicate their wishes due to a medical emergency. This document is part of a larger set of documents known as Advance Health Care Directives, which may also include a health care power of attorney, where an individual designates another person to make health care decisions on their behalf. Arizona's statutes provide the framework for creating a valid living will, which typically requires the document to be in writing, signed by the declarant, and either notarized or witnessed by at least one adult who meets certain criteria. The living will becomes effective when the declarant is diagnosed as being in a terminal condition or in a persistent vegetative state and is unable to communicate their wishes. The document can include instructions to provide, withhold, or withdraw life-sustaining treatment and other specific wishes regarding health care. Arizona law also recognizes Do Not Resuscitate orders (DNRs), which are separate directives indicating that the individual does not wish to have cardiopulmonary resuscitation (CPR) in the event of cardiac or respiratory arrest.