In the wake of the 11 September 2001 terrorist attacks in the United States, organizations involved in emergency management at the local, state and federal level were mandated to utilize the Incident Command System (ICS) to structure on-scene response efforts. The system is currently relied upon as an organizing mechanism for response in the United States, and its widespread use outside of the United States is being advocated. Yet, there is little evidence that the system is consistently used as designed or a salve to common response problems. This paper reviews the evolution of ICS in practice and the available research on its use and effectiveness. The review makes clear that more research on the system is urgently needed.