Migraine is a highly prevalent headache disorder that has a substantial impact on the individual, society, and the family. In this chapter, the burden of migraine will be reviewed, emphasizing the population-based studies that used standardized diagnostic criteria. The chapter highlights descriptive epidemiology, burden of disease, patterns of diagnosis, and treatment. Although migraine is a remarkably common cause of temporary disability, many migraineurs, even those with disabling headache, have never consulted a physician for the problem. Prevalence is highest in women, in persons between the ages of 25 and 55 years, and, at least in the United States, in individuals from low-income households. Nonetheless, prevalence is high in groups other than these high-risk groups.