The death of a person refers to the permanent cessation of all integrated brain function. Brain death denotes a state where all brain function has permanently ceased, but the heart continues to beat. There is no global consensus in diagnostic criteria, and the guidelines and protocols regarding the confirmation of brain death vary from country to country. This article is based on the protocol applied in Finland. Declaration of brain death follows a certain set of tests that demonstrate the complete absence of brain function (brain stem function in the UK). Provided that the cause of the irremediable brain damage is known and the absence of all cranial nerve reflexes has been confirmed with clinical tests, death can be declared whilst the heart continues to beat. At least two physicians, of specified status and experience, are required to act together to diagnose brain death.