The objective of this chapter is to introduce the triage. Triage is process of prioritizing patient treatments based on severity of condition. This chapter covers the color codes, description and examples of triage and types of triage. Types of triage are primary triage and secondary triage. Primary triage is an assessment for prioritizing of patient treatment based on the severity of their condition in a mass casualty situation due to chemical biological, radiological or nuclear event. Secondary triage involves a determination of the severity status once a decision has already been made that a patient is to be entered into the system (primary triage). Some examples of triage include massive hemorrhage, tension pneumothorax, major amputations, internal hemorrhage, and arterial bleeding.