Brain death is a valid cause of death certifi cation in a patient, especially in terms of organ donation. There are few situations in which the legislator has proposed further examination for certifi cation. We report the case of a patient with Guillain Barré syndrome, which came to simulate a state of brain death due to motor impairment in full, including intrinsic ocular muscles. The lack of a necessary and suffi cient condition for declaring the patient's death led to request additional examinations, in this case an electroencephalogram, which determine the normality of brain electrical activity. It emphasizes the need to comply strictly with the criteria for determining brain death and not to request additional examinations inhibited in a position of doubt, even though the law does not always contemplated.