We describe the epidemiology and comorbidities of migraine, which affects 12% of adults in occidental countries. Prevalence is three times higher in women, but 6% of men are affected, making it the most prevalent neurologic disorder in men. Although migraine is a remarkably common cause of temporary disability, many migraineurs have never consulted a physician for the problem. Many disorders are comorbid with migraine. For some such as depression, the association has been well described, but for others, the relationship has been recently suggested, such as in the case of clinical and subclinical vascular brain lesions and coronary heart disease.