Data from the 1989 National Health Interview Survey concerning migraine occurrence and impairment were analyzed to assess the impact of migraine on the US population. About four of every one hundred persons in the United States were found to have migraine, accounting for nearly 10 million individuals. Migraine was most prevalent in those aged 25 to 44 years and was about 2.5 times more frequent in females than males. Migraine was most common in whites (85%) and those with low household income. In women, migraine prevalence increased with the level of education. About 10% of migrainous children missed at least one day of school over a two-week period due to migraine; nearly 1% missed four days. Migraineurs were bedridden for about three million days per month and had an estimated 74.2 million days per year of restricted activity due to migraine. The potential cost of lost productivity was estimated at $1.4 billion per year for the estimated 6,196,378 migraineurs who worked outside the home. It is difficult to derive similar estimates for costs of lost productivity in housewives; however, housewives experienced an estimated 38 million days per year of restricted activity. Eighty-five percent of females and 77% of males reported a physician visit at some point for their migraine. Migraine is a relatively common disease whose social and financial impact has been poorly understood.