Patients with headache commonly seek care at an emergency department (ED). Patients with headache in fact account for between 1 and 2% of admissions to an ED. Therefore the ED physician must recognize symptoms and characteristics of headache that signal a potential significant organic problem in order to select appropriate tests and treatment. Key to the correct management of headache in ED is a careful, thorough history of the patient. This article summarizes what the ED physician should take into consideration in order to distinguish who simply needs reassurance and analgesia and who needs further investigation.