The chapter discusses the concept of death, various aspects of brain death, its importance for organ donation, and legal and ethical issues in determining brain death. Discussion concerning the definitions of death belongs to the field of legal medicine. The concept of the moment of death has changed through years. Various tests were used for a long time to find the validity of the major three organs of life. A determination of death must be made in accordance with accepted medical standards and following the guidelines that professional associations have established for determining circulatory or brain death. Awareness about brain death is extremely low in India. Process of death, limitations of brain death criteria, and controversies over brain death diagnosis are also discussed in this chapter.