Migraine is a highly prevalent headache disorder that has a substantial impact on the individual and society. In this article, we review the burden of migraine, emphasizing the population-based studies that used standardized diagnostic criteria. We highlight descriptive epidemiology, burden of disease, patterns of diagnosis, and treatment. We focus on the epidemiology and burden of probable migraine, a subtype of migraine where just one clinical feature is missing. We finish by describing approaches to improving healthcare delivery for migraine and probable migraine. 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. Probable migraine is a prevalent form of migraine, and like migraine with and without aura it produces decrements in health-related quality of life and increments in disability relative to control subjects.