A terrorist attack on downtown Washington, DC will result in hundreds if not thousands of people needing medical assistance. Hospital emergency departments are not designed to deal with disasters of this magnitude. They will be quickly overwhelmed by the influx of patients and medical personnel converging on their facility. Yet additional medical personnel are available to help, including those in other parts of the hospital and in ambulatory facilities. There are two prerequisites for the effective mobilization and utilization of additional medical facilities and personnel. The first is that a disaster plan be in place. The second is that there exists a communication network of healthcare personnel that can be activated by the disaster plan. We propose to create a communication network that an emergency department can use to mobilize medical personnel during a terrorist attack or other disaster. We will use wireless-enabled handheld computers along with several redundant wireless protocols for reliable and portable communication. In the event of a terrorist attack, the system will alert and mobilize medical personnel. Once on the scene, physicians, nurses, and paramedics will use the system to follow through with a specific disaster plan, upload clinical data to a central command center, provide two-way communications for treatment consultations, and provide status updates from the scene. During Phase I, we will develop and evaluate a prototype system. This will determine the feasibility of our approach and provide a basis for the development of a complete system during Phase II.