Background: Multicriteria Decision Analysis is a tool capable of supporting decisions with multiple criteria. Notwithstanding its con rmed value in the health area; so far, no studies have been found to help prioritize victims in the Emergency Medical Service, EMS. Since decision making within EMS involves multiple criteria, it is essential to nd techniques and tools that encompass such elements, as to reduce errors. As to address this gap, the current research developed a multicriteria decision model to help prioritizing victims in the Brazilian EMS, which are still managed as a manual task. Methods: To reach such endeavour, it was formed an expert panel and a discussion group, tasked to de ne the limits of the problem, and to identify the evaluation criteria for choosing a victim, amongst four alternatives derived from clinical and traumatic diseases scenarios of absolute priority in emergency situations occurrences. For prioritization, an additive mathematical method was utilized, aggregating criteria in a exible and interactive version - FiTradeoff. Results: The present work contributed to victims' prioritization by using the multicriteria decision support methodology which led to the identi cation of twenty- ve evaluation criteria to guide the decision. It was noted that the protocols to guide regulating physicians do not consider all the criteria for prioritizing victims in an environment of resource scarcity. In the prioritization simulation composed of four demanding victims and only one available ambulance, the proposed model supported the decision by suggesting the prioritization of Victim 2. Conclusions: From the identi ed improvement points, the developed decision model was able to improve the regulatory action of medical professionals. The elicitation procedure enabled the identi cation of criteria that, albeit well known, were not formalized by the current guidance protocols, which could contribute to contradictions and conicts across the decision chain. Last, but not least, the proposed model could support decision making under the guarantee of a rational and transparent decision-making process that could be applied in other EMS.