To perform a systematic review of the properties and results of the studies that their approaches are lean management in emergency departments and the factors which influence on their performance.The necessary information in the first stage was collected by searching these keywords: "Lean principles" "Lean Six Sigma", "Lean Process", "Lean thinking", "Lean Methodology", "Toyota Production System lean processing", "lean techniques", "emergency department", "emergency medicine", "emergency room" and "emergency care " . And in the next stage the keywords such as "lean management" and "emergency" was collected from SID, Medlib, IranDoc, Google Scholar, MagIran, IranMedex data bases. For extracting the data data-extracting forms was prepared. The information we got from the forms was organized in information-extracting forms and was analyzed manually. The diagrams were drawn in Excel: 2010.Finally, 26 essays have been included. Most of the studies were accomplished in Canada and U.S.A. only in one of the cases, the authors used the control group. Each of these terms, "lean techniques" and "lean principals", with five times repetitions had the highest frequency. The most important team of implementation of lean management included: hospital management team or the manager of Emergency department, physicians, nurses, staffs and external counselors. Generally, 51 indicators were studied which among them the length of stay and the timing had the most frequency. After implementation of lean management, almost all studied indicators have significantly improved. 14 barriers, 14 facilitators and 10 effective factors were recognized in implementing the lean management.According to the studies, responsibility of organization's senior management and his/her supports; increasing the knowledge of the characteristics and dimension of lean among the providers of health service; and decreasing the resistance and consulting with external counselors can have great effect on the success of lean management.