Mass casualty is a sporadic event precipitated by natural or man made causes which can be defined as the need for medical care exceeding the ability to provide it. Many literature reports of mass casualty evolutions depict scenes of chaos and confusion, leading to a need for a standardized approach to assessment, triage, and initial resuscitation. Even with the advent of trained emergency medicine specialists to direct these activities, such a framework would seem highly desirable for other participating primary care specialists. Additionally, a uniform system might be particularly useful in the mass casualty situation where international rescue teams converge on one disaster site. Advanced Trauma Life Support (ATLS) is a standardized approach easily adaptable to triage and resuscitation of multiple patients. Its use and effectiveness in mass casualty, however, has not had prior mention in the literature. This paper presents the first reported adaptation of ATLS principles to mass casualty during the invasion of Grenada. The bulk of 76 patients brought to the Primary Casualty Receiving and Treatment Center (PCRTC) were triaged, stabilized, and resuscitated by three PGY-1 trained, non-trauma-experienced physicians. During the primary survey, 8 major life threatening problems were identified and immediately corrected without loss of life. The ATLS system seemed to provide a comfortable framework for these partially trained physicians. Arguments for its adaptation and use as an international system approach are discussed.