Headache disorders constitute a public-health problem of enormous proportions, with an impact on both the individual sufferer and society. Epidemiological knowledge is required to quantitate the significance of these disorders. The effects on individuals can be assessed by examining prevalence, distribution, attack frequency and duration, and headache-related disability. The socio-economic burden includes both direct costs associated with health care utilization and costs associated with missed work due to sickness absence or reduced efficiency. The individual and socio-economic burden of headaches is substantial. Headache disorders deserve more attention, especially concerning strategies leading to adequate primary prevention, diagnosis and treatment.