The definition of the Ambulance Emergency Medical System Structure (EMSS) is an important issue in the healthcare sector. The EMSS consists of the number and location of ambulance bases required to satisfy an established service level or optimize a certain criterion. An important effort of academic research has been realized to determine the optimal EMSS based on the optimization of single objectives. However, as evidenced by the different criteria utilized in the vast literature developed, this issue could be discussed under several criteria simultaneously such as demand coverage and ambulance response time concepts. In this paper, we will undertake a multicriteria approach for supporting decision makers to determine their most preferred EMSS. This approach is applied to the Monterrey metropolitan operations of the Mexican Red Cross. Results of the application are provided.