Biološka oporuka nije oporuka u smislu nasljednog prava. To je anticipirana izjava (naredba) koju neka osoba daje u odnosu na njen medicinski tretman ako zapadne u stanje nesposobnosti za rasuđivanje. Ima, dakle, učinak za života te osobe. Isto tako to nije eutanazija ako se pod tim misli na umjetan, ljudskom odlukom određen prekid nečijega života. Ima, međutim, veze s eutanazijom ako se pod tim (a što je jedino pravilno) misli na „dobru, toplu i mirnu smrt“ ako do nje dođe tijekom medicinskoga tretmana u kojem ta osoba može pristajati, ali može i odbijati neki dijagnostički ili terapeutski postupak. Smrt nije primaran ni glavni cilj nego samo jedna od mogućih posljedica. Bitan je cilj dostojanstveno življenje i starenje. U radu su opisana stanja pravne regulacije u Italiji (koja je nedavno donijela poseban zakon) i u RH. Također su opisane mogućnosti i oblici primjene cijelog instituta.; In this work the author describes the present situation of Italian and Croatian living will law regulations, as well as circumstances and forms of the implementation of the whole legal institute. Living will actually not a will known in inheritance law, because it is an anticipated statement (order) made by a person in relation to his or her medical treatment in case of a possible future reasoning inability, which means that it has effect on the life of that person. Furthermore, it cannot be understood as euthanasia in the meaning of an artificial termination of one’s life caused by a person’s decision. However, it can be linked to euthanasia - which is in fact solely right - if therewith one thinks about of a good, warm and silent death, in case it happens during a medical treatment by accepting or refusing a diagnostic or a therapeutic procedure, as death is neither a primary nor a main goal of the living will, but only one of the possible consequences, because the main intention is dignified living and ageing.