The diagnostic value of greater occipital and supra-orbital nerve blockades in patients with cervicogenic headache, migraine without aura, and tension-type headache was investigated. The pain reduction after greater occipital nerve blockade was significantly more marked in the cervicogenic headache group than in the other categories. Moreover, pain reduction in the forehead was generally only found in the cervicogenic headache patients (77%). Pain reduction (in %) was significantly more marked following the greater occipital than the supra-orbital nerve blockade. The volume effect per se was evaluated by saline injection. This procedure did not result in distinct pain reduction. The effect obtained in cervicogenic headache is, accordingly, probably due to the local anaesthesia. The present results support the postulate that different pathogenetic factors probably are responsible for cervicogenic headache, tension-type headache, and migraine without aura.