The emergency physician plays an important role in disaster planning and management. Some disasters will require the removal of a segment of the population for their own safety; this removal is referred to as mass evacuation. This aspect of disaster planning is frequently ignored or, at best, given a few short sentences in overall plans for coping with disasters. Very little has been written on this important aspect to permit one to make intelligent evacuation plans. This article summarizes previous studies on the reactions of people to, and their behavior during, actual mass evacuations. The information is used to outline important points that must be addressed by all those involved in disaster plans so that people may be removed from danger quickly, with as few problems as possible.