A firefighter Incident Commander (IC) is responsible for organizing, coordinating and making decisions in most urban emergencies, such as fires and car crashes. The lack of supporting information and the limitations of the radio systems push the IC to make decisions with little or no information; therefore his actions tend to be improvisations. This article presents a decision support system that allows the IC to address medium-sized urban emergencies, providing him on-demand information and also recommendations to address the event. The system was evaluated by comparing the information that it provides, with those required by the IC during past emergencies. The system was also evaluated by firefighter's commanders during a focus group session. The obtained results indicate that the proposed system is able to support the decision making process performed by IC during medium-sized emergencies. © 2013 IEEE.