Background: Earthquake has always been a serious threat for humans' health and properties. In this regard, the most urgent services for people after the occurrence of incidents and disasters, especially earthquake, is health services. Iran due to its geographic location along the Alpine-Himalayan belt is vulnerable to the occurrence of earthquakes with magnitudes of 6 and 7 on the Richter scale. Prevention of earthquake is impossible; however, it is important to use the lessons learned to reduce the physical and financial damages in similar future incidents. This study was conducted with the objective of examining the lessons learned by the workgroup of Health and Treatment in response to 7.3 magnitude Kermanshah Province earthquake. Materials and Methods: In This case study, the triangulation method including interview, participatory observation and expert panel in three sections of prehospital emergency services, medical center, and health and treatment centers, was used to assess the performance of health and treatment workgroup in response to Kermanshah earthquake. For this purpose, in addition to recording the information resulting from observation by the researchers, the reports related to EOC (Emergency Operations Center) of Kermanshah and expert assessors were examined. Furthermore, interviews were conducted with experts, directors, commanders and responsible authorities in the field of incident and the State Emergency Organization central headquarters' staff. Finally, the collected data were analyzed. Results: Based on the study findings, the positive points were the rapid response by the Emergency and Health system organization, effective command on the scene of incident from the first moments, fine management of human resources and the injured within reasonable time, dispatching more than 7350 injured people to treatment centers in less than 20 hours, carrying out 1980 successful operations in less than 3 days, establishing and running 6 mobile hospitals in less than 12 hours, complete supply of blood and blood derivatives, medicines, equipments and specialist force, and sustainability of health and treatment services in less than 24 hours. However, the most important problems were deficiency in protocol, absence of special assessment team and failure to use rapid assessment national standard, lack of national response plan in crisis management and the high vulnerability of hospitals' infrastructures. Conclusion: Although in this earthquake, thanks to positive steps taken by health and treatment workgroup, great progress was observed in response operations in the area of health; based on the study findings, there are challenges that the health system should resolve in order to improve health services in incidents and disasters. Developing the emergency organization and especially emergency air service, advancement of the status of the State Crisis Management Organization, accurate planning for aid services such as temporary sheltering and provision of latrines and bath and establishing mobile hospitals...