Implantable cardiac pacing and defibrillation devices are effective and commonly used therapies for patients with cardiac rhythm disorders. Because device implantation is not easily reversible, as well as the high healthcare costs inherent in device use, a clear understanding of the clinical benefits relative to costs is essential for both appropriate clinical use and rational policy making. Cardiac implantable electronic devices (CIEDs) have been among the best-investigated therapies in medicine; these devices have been the topic of numerous clinical and economic evaluations during the past 30 years. However, many important questions remain unclarified. We review the evidence supporting the clinical benefits of CIEDs, including effectiveness in extending survival as well as improving quality of life. We also summarize the economic studies that have investigated costs associated with these devices and their overall cost effectiveness, and we highlight important potential areas for future research.