The current Estonian guideline for determination of brain death dates back to 2002. It defines clinical signs and symptoms. There are areas, however, not covered in this guideline, which physicians face in everyday life. The guideline does not define the duration of the observation period to confirm brain death. Nor does it explain the method for apnoea testing or situations that require ancillary tests. Many countries have recently updated their guidelines for determination of brain death. The Estonian guideline needs updating as well.