Use of neurologic criteria to pronounce death, although accepted by many, has caused controversy among physicians, lawyers, legislators, philosophers and theologians. Scientific information was summarized that establishes the ability to determine the state of brain death with certainty on the basis of presently available clinical and laboratory criteria. The concept of brain death was demonstrated to be in accord with secular philosophy and the 3 major Western religions. The need for legislative recognition that death may be pronounced on the basis of neurologic criteria was documented. The present status of judicial and statutory law relating to the determination of death in the United States was reviewed.