Personnel from the 72 facilities with the most experience in MR imaging were surveyed, and 45 questionnaires were returned with data to study the economics and use of MR imaging facilities. The data from 1990 were compared with results of studies done in 1985 and 1987. The facilities studied were highly selected, and the data and conclusions are unlikely to be representative of all MR facilities currently operational in the United States. The "typical" MR unit operated about 66 hr per week and imaged 68 patients. Most procedures were examinations of the head and spine (73%), with examinations of bone and joint increasing in frequency (17%). Scheduling delays for both inpatients and outpatients have decreased since 1987, indicating that clinical demand is being met by MR facilities. The global (technical plus professional) charge for an examination was approximately $950, and the charge for IV contrast material was an additional $200. IV contrast material was used in approximately 40% of head and 20% of spine studies. The typical MR unit in 1990 was used to examine more than 3000 patients per year at a charge of approximately $750 each for the technical component. Technical billings for each unit were approximately $2.3 million, and net revenues were almost $1.9 million. We estimate the annual operating cost of an MR unit in 1990 was $1.3 million, so the typical MR unit had an annual net profit of approximately $500,000. This is a considerable improvement from the economic position in 1985, when each MR unit was losing approximately $400,000 annually. We conclude that experienced MR imaging facilities are now profitable owing to increased efficiency and continually rising charges. We suggest the economic historical pattern demonstrated by MR imaging (large losses initially followed by profitability within several years owing to increased efficiency and higher charges) is a typical pattern for many new technologies with the current medical payment system in the United States.