Performance measurement systems is an issue that has been intensively studied, both by scholars and by the practioners. The Maritime Transportation area of Petrobras has identified the need to re-evaluate its performance measurement system, which motivated this thesis, which has the purpose of proposing an improved performance measurement system. In order to achieve that, the current performance measurement system has been assessed, identifying, describing and analyzing the main performance measures currently used by the Maritime Transportation area in connection with the performance of its fleet. The research method applied consisted in literature review, collecting data from the company`s information systems, carrying out semi-structured and structured interviews, as well as validation interviews, in order to assess the current performance measurement system of the fleet, propose improvements and verify the extent of the suggested modifications. As a result, it has been identified the need to review three out of five measures, resulting in a proposition of seven measures to evaluate the performance of the fleet, such proposition being validated by the Maritime Transportation area through interviews. The validation of the proposed measuring method for some of the performance measures has been reinforced by the use of historical data for further anlysis and presentation to the managers and other interviewed persons in the Maritime Transportation area.