Abstract The definition of death lost its significance in favor of brain death. Brain death is a permanent cessation of all functions of the brain in which though individual organs may function but lack of integrating function of the brain, lack of respiratory drive, consciousness, and cognition confirms to the definition that death is an irreversible cessation of functioning of the organism as a whole. In spite of medical and legal acceptance globally, the concept of brain death and brain-stem death is still unclear to many. Brain death is not promptly declared due to lack of awareness and doubts about the legal procedure of certification. Many brain-dead patients are kept on life supporting systems needlessly. An attempt has been made to highlight the history and concept of brain death and brain-stem death; the anatomical and physiological basis of brain-stem death, and criteria to diagnose brain-stem death in India.