Side-locked unilaterality and specific localization of pain are not as well-defined clinical characteristics in long-lasting headaches (duration more than 4 hours) as they are in short-lasting forms. We examined side-locked unilaterality and pain distribution at onset and at peak headache in 74 patients with different forms of long-lasting headache: migraine and tension-type headache (IHS) and cervicogenic headache (according to Sjaastad et al). Side-locked unilaterality of pain was found in all forms, but to differing extents - 20.8% in migraine, 12.5% in tension-type headache, while it was a mandatory criterion for cervicogenic headache. The pain tended to localize anteriorly, particularly at onset, in migraine; was more diffuse in tension-type headache; and always began in the occipitonuchal region in cervicogenic headache. Our results may contribute to a better clinical definition of long-lasting headaches.