MRI development in the United States is reviewed from 1983 to the present with the intent of projecting future utilization and reimbursement. Since 1992, a decreasing rate of new installations and an aging installed base have markedly lowered the ratio between fixed and variable costs, thereby improving the ability to project cost per study. Variable costs are now estimated to average $175 to $200 per examination, up sharply from earlier reports. Actual costs per study usually exceed $400, even for high volume sites. Major cost contributors are reviewed and methods for identifying impediments to efficient operation are suggested.