Publisher Summary This chapter discusses the threat posed by intentional and unintentional electromagnetic interference (EMI) to the integrity of health care organizations. EMI has the ability to degrade or totally disrupt the health care delivery. EMI can be natural (static electricity or lightning) or man-made. Intentional EMI (IEMI) is facilitated by the proliferation of the technological advances that have produced high-energy radiofrequency (RF) sources and more efficient antennas. The classic IEMI paradigm is the result of the high-altitude detonation of a nuclear weapon. EMI can be reduced or eliminated in all but the most severe cases through proper design and mitigation techniques. A thorough vulnerability analysis of existing equipment, especially high-value items, will result in a number of effective strategies for mitigating the effects of EMI. It is imperative that biomedical engineers understand the problem and institute robust mitigation programs to ensure the ability to survive in such a crisis.