Older adults (aged 75 and over), non-Hispanic black persons, poor persons, and persons with Medicaid coverage were more likely to have had at least one emergency department (ED) visit in a 12-month period than those in other age, race, income, and insurance groups. Among the under-65 population, the uninsured were no more likely than the insured to have had at least one ED visit in a 12-month period. Persons with Medicaid coverage were more likely to have had multiple visits to the ED in a 12-month period than those with private insurance and the uninsured. ED visits by the uninsured were no more likely to be triaged as nonurgent than visits by those with private insurance or Medicaid coverage. Persons with and without a usual source of medical care were equally likely to have had one or more ED visits in a 12-month period.