Seven hundred nineteen young patients attending 21 Italian headache care settings were evaluated by a diagnostic headache interview and a neurological examination. Headache disorders were classified according to the current 1988 criteria of the International Headache Society (IHS); 54.9% of the patients suffered from migraine, 33.9% from tension-type headache, 1.9% from secondary headache, and 3.4% had non-classifiable headache. A further 5.9% of the patients were not classified due to incomplete questionnaires. Of the 395 patients with migraine, 44.5% were affected by migraine without aura, 29.9% by migraine with aura, 1.3% from other migraine forms, and 24.3% by migrainous disorders which do not fulfill the 1988 IHS diagnostic criteria for headache. Among the 244 patients with tension-type headache, 51.6% had episodic tension-type headache, 15.2% chronic tension-type headache, and 33.2% headache of the tension-type which does not fulfill the 1988 IHS criteria for episodic and chronic tension-type headache. In young migraine patients, pain was of a pulsating type in 55.7%, severe in 57.8%, unilateral in 42.6%, and aggravated by routine physical activity in 38.9%. Tension-type headache was described as pressing in 73.8%, mild or moderate in 75.7%, bilateral in 87.4%, and not aggravated by routine physical activity in 85.5%. The duration of pain was less than 2 hours in 35% of the cases in migraine sufferers and less than 30 minutes in 26.7% of tension-type headache sufferers. Nausea, phonophobia, and photophobia were present in at least half of the migraine patients and in one third of tension-type headache patients, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)