Increased use of ICDs in patients with cardiac disease has the potential to strain national health care budgets because of the large numbers of eligible patients and the high cost of the ICDs. Randomized trials show ICDs increase life-expectancy in some groups of patients and also increase total medical costs significantly. ICDs exemplify the role of new technology as the main force behind rising health care costs. ICDs have not been used in all eligible patients, in part because of cost, but also because of patient resistance and a shortage of specialists able to implant and manage complex ICDs. The cost-effectiveness of ICDs would be improved by development of simpler and cheaper devices, and by better tools to identify patients who benefit from an ICD.