In order to study the prevalence of frequent headaches among the medical students of Athens University, an epidemiological survey was carried out among 588 medical students (318 men and 270 women), with mean age 23.5 years. Two questionnaires were designed for the study: one general, consisting of 10 questions and a second one, specific for headache sufferers, consisting of 117 questions. All those with headache who voluntarily completed the two questionnaires also underwent a neurological examination. Thirty point eight percent of men and 50.3% of women reported various headache attacks during the previous 6 months (39.6% in both sexes). However, only the 11.9% of students (from both sexes) reported that they suffered from disturbing headaches. The 6-month prevalence of migraine was 2.4% and 9.5% for tension-type headache (in both sexes). Cluster headache was not traced. The prevalence of nonclassifiable headaches (according to the criteria of the International Headache Society) was 0.85%. Headache was correlated to sex (more frequent among women) and anxiety level (Hamilton scale for anxiety). Headache prevalence was not correlated to smoking and social class.