A national survey was conducted to examine the extent of adoption and use of nuclear imaging procedures in cardiology in hospitals by 1979 and to develop estimates for 1983. The data are based on the responses of 171 hospitals from a representative 200-hospital sample stratified for region, bed-size, and teaching status. Extrapolating the data, it is estimated that 2,106 hospitals nationally use cardiac nuclear imaging. In 1979, hospitals with at least 200 beds performed an estimated 396,000 cardiac nuclear imaging studies at a cost of $93 million. By 1983, it is estimated that 4,061 hospitals had the capability to perform cardiac nuclear imaging and that national expenditures would exceed $200 million (noninflated dollars). Although cardiac nuclear imaging procedures have been demonstrated to be valuable in detecting coronary artery disease or measuring ventricular function, these procedures were rapidly being adopted by the medical community at a time when only limited information about their effectiveness and efficiency are available.