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 Mississippi, a living will is recognized under the state's Advance Health Care Directive Act. This legal document 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. The living will can specify whether the declarant wants to receive, withhold, or withdraw life-sustaining treatments if they are in a terminal condition or a state that is considered irreversible. Mississippi law allows for the creation of an Advance Health Care Directive, which may include a living will and a health care power of attorney, where the declarant appoints an agent to make health care decisions on their behalf. Additionally, Mississippi residents can establish Do Not Resuscitate orders (DNRs), which instruct medical personnel not to perform CPR if the patient's breathing or heart stops. These documents are typically part of the state's health care, probate, or estates statutes and are crucial for ensuring that an individual's health care preferences are respected.