Headache may be the most common presenting symptom of unruptured intracranial aneurysms. Unruptured intracranial aneurysm can be found in the work-up for headache but direct causality is not clear. Most of the headaches have been thought to be incidental symptoms of unruptured intracranial aneurysms. If high-risk patients with symptoms such as headache could be selected it would help in diagnosing unruptured intracranial aneurysms. Many aspects of unruptured intracranial aneurysm-associated headaches are unclear, including the mechanism, discriminating characteristics, and localization. This article reviews basic knowledge on cerebral aneurysm and headache, and describes the possible mechanism and characteristics of aneurysm-associated headaches.