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 Georgia, the determination of death is governed by the Georgia Death Investigation Act. According to O.C.G.A. § 31-10-16 (Georgia Code), a person 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, according to ordinary standards of medical practice. The pronouncement of death must be made by a licensed physician. It is important to note that the use of artificial means of support can make it difficult to determine if the spontaneous functions have ceased, but death can still be pronounced when brain activity is irreversibly absent. The formal pronouncement of death by a physician does not establish the legal cause, manner, or exact time of death; these are determined separately, often through a death certificate and, if necessary, an autopsy or investigation by a medical examiner or coroner.