In this report, data from the RAND Health Insurance Experiment (HIE) were analyzed to answer significant research questions about chiropractic health services. The HIE was a population-based, randomized controlled trial that tracked the use of medical services and the health status of enrollees over a three- or five-year period. Information was taken directly from the HIE claims form and combined with demographic and health status information collected on the HIE participants at enrollment. Chiropractic users were more likely than nonusers to be white, between the ages of 18 and 50, high school graduates, and married. Cost-sharing decreased annual chiropractic expenditures by about one-half. Chiropractic episodes of care were among the lowest in total cost but were among the highest in outpatient costs.