Cardiopulmonary arrest has long been accepted as an unquestionable definition of death. An advent of cardiopulmonary resuscitation and artificial ventilation along with the development of organ transplantation has prompted the emergence of the concept of brain death. The criteria for brain death are based mainly on the clinical examination of coma, apnea and total loss of brain stem function. Although organ transplantation by donor brain death has increased in Korea over recent years, there is still a substantial shortage of donor organs compared to the demand. Improvement of government policies and changes of social culture for organ donation are needed for the activation of organ transplantation by donor brain death. Pediatricians have an important role for the search of potential donors in cases of brain death and optimal medical care for successful organ transplantation.