Abstract: Objective: analyze the effectiveness of the implementation of the Lean Healthcare sys-tem at the emergency room of the Clinical Hospital of the Federal University of Uberlândia (HC-UFU), based on a comparison of hospital indicators obtained over the three phases corre-sponding to the period of one year before the implementation (T1), the year during the imple-mentation (T2) and one year after implementation (T3). Material and Methods: this is applied research, classified as a case study, exploratory, descriptive that is developed in stages. Based herein on the search for hospital indicators, as occurred in the implementation process of Lean in Emergencies at the HC-UFU and a description of the implemented Lean system. Results and Discussions: during the period where it was possible to collect data relevant to the NEDOCS and LOS indicators, the motivation of the teams grew, but with a notable tension between municipal management and hospital management. It was found that, despite the fluctuations, the patient length of stay in the Emergency Room remained high. Noteworthy here is that with the excep-tion of the variable of female deaths before 24 hours of hospitalization, all other variables showed percentage increases before and after the intervention. Conclusion: the methodology followed for the implementation of Lean in Emergencies in the emergency sector of the hospital did not produce an improvement in hospital indicators.