The determination and pronouncement of when a person has died has medical, ethical, and legal implications. Laws vary from state to state, and death is usually defined in a state’s statutes.

Definitions and terminology may vary from state to state but generally a person is dead when, according to ordinary standards of medical practice, there is irreversible cessation of the person's spontaneous respiratory and circulatory functions. If artificial means of support preclude a determination that a person's spontaneous respiratory and circulatory functions have ceased, the person is dead when, in the announced opinion of a physician, according to ordinary standards of medical practice, there is irreversible cessation of all spontaneous brain function.

Death occurs when the relevant functions cease. But a formal pronouncement of death is not a legal determination of the cause, manner, or time of death.

In Utah, the determination of death is governed by the Utah Uniform Determination of Death Act. According to this act, an individual is legally recognized as dead if there is an irreversible cessation of circulatory and respiratory functions, or if there is an irreversible cessation of all functions of the entire brain, including the brain stem, in accordance with accepted medical standards. This definition allows for the recognition of brain death as a legal definition of death, which is significant in cases where life support technology is used. The pronouncement of death must be made by a qualified physician. It's important to note that while the pronouncement of death establishes that death has occurred, it does not establish the legal cause, manner, or exact time of death; these are determined separately, often through a death certificate or during a coroner or medical examiner's investigation.