In this article is presented an integer linear model with an objective function for maximizing the usage of operation rooms (O.R.). The model arises after applying a proposed technique using the Six Sigma DMAIC approach that allows the review of the process in order to identify situations that can be improved. Based on the mentioned technique, different problems arise, having the occupation level of the operation rooms as the most important issue, with which is possible identify the vulnerable elements of the process, and based on statistical tools the values of the parameters that must be considered in order to build the model, are determined. The solution technique used to solve the model is the Branch and Bound algorithm with the CPLEX solver.