We review death, thanatology and bioethics concepts and precepts, the value scale and hierarchization; the changes in death vision according to culture, religion and hierarchy, changes in perception of, according to culture, religion and mores in different communities and times, as well with scientific and technological advances. We analyzed patient's reactions to death, and the reactions of people close to them. We describe and analyze the principal bioethical dilemmas associated with death: therapeutic overkill or dysthanasia, passive and active euthanasia, assisted suicide, orthothanasia, and organ transplants. We discuss the relationship between death and science, bioethics and thanatology, as a necessary discipline today.