Mass casualty incident involves the use of limited resources for multiple casualties. The emergency physician must be familiar with both prehospital and hospital plans for mass casualty care in order to facilitate optimal care and to maintain the continuum from field care to definitive treatment. It is essential that the emergency physician become involved in the disaster planning processes to ensure that the victims receive the best care available under the circumstances and that the safety and emotional well-being of both prehospital and hospital personnel are assured. Emergency physicians involved in prehospital care should be certain that the local EMS system has adequate training and chances to update their skills and knowledge. Disaster drills of the EMS system are excellent ways to practice, to identify weaknesses, and for preplanning to enhance disaster medical care.