Mass-casualty triage has developed from a wartime necessity to a civilian tool to ensure that constrained medical resources are directed at achieving the greatest good for the most number of people. Several primary and secondary triage tools have been developed, including Simple Treatment and Rapid Transport (START), JumpSTART, Care Flight Triage, Triage Sieve, Sacco Triage Method, Secondary Assessment of Victim Endpoint (SAVE), and Pediatric Triage Tape. Evidence to support the use of one triage algorithm over another is limited, and the development of effective triage protocols is an important research priority. The most widely recognized mass-casualty triage algorithms in use today are not evidence-based, and no studies directly address these issues in the mass-casualty setting. Furthermore, no studies have evaluated existing mass-casualty triage algorithms regarding ease of use, reliability, and validity when biological, chemical, or radiological agents are introduced. Currently, the lack of a standardized mass-casualty triage system that is well validated, reliable, and uniformly accepted, remains an important gap. Future research directed at triage is recognized as a necessity, and the development of a practical, universal, triage algorithm that incorporates requirements for decontamination or special precautions for infectious agents would facilitate a more organized mass-casualty medical response.