Headache is one of the most common manifestations of non-traumatic intracranial hemorrhage, which is an uncommon, but not rare, cause of cardiac arrest in adults. History of a sudden headache preceding collapse may be a helpful clue to estimate the cause of out-of-hospital cardiac arrest (OHCA). Medical records of witnessed OHCA patients were reviewed to identify those who complained of a sudden headache preceding collapse, and the incidence of intracranial hemorrhage among them as well as their clinical characteristics was investigated retrospectively. During the 12-month period, 124 patients who sustained a witnessed OHCA were treated. Among them, 74 (60%) collapsed without any pain complaint, and only 6 (5%) complained of a sudden headache preceding collapse. All of the six patients were resuscitated: four had a severe subarachnoid hemorrhage (SAH), while the other two had a massive cerebellar hemorrhage. By contrast, 39 of the 74 patients who collapsed without any pain were resuscitated. Among them, another six patients were found to harbor an SAH. Thus, a total of 12 among the 124 witnessed OHCA (10%) sustained a fatal intracranial hemorrhage. While OHCA patients who collapse complaining of a sudden headache are uncommonly seen in the emergency room, they have a high likelihood of harboring a severe intracranial hemorrhage. It should also be reminded that approximately half of patients whose cardiac arrest is due to an intracranial hemorrhage may collapse without complaining of a headache. The prognosis of those with cerebral origin of OHCA is invariably poor, although they may relatively easily be resuscitated temporarily. Focus needs to be directed to avoid sudden death from a potentially treatable cerebral lesion, and public education to promote the awareness for the symptoms of potentially lethal hemorrhagic stroke is warranted.