BACKGROUND During the last three decades, ethics committees have been formed with a growing trend. These committees have a satisfactory and effective impact on the pattern of patient care and its performance. The medical ethics committee is considered one of the most active committees in hospitals, having the aim of providing necessary approaches for the optimal use of the findings in empirical science and diagnostic treatment and observance of Islamic noble values in performing medical affairs. OBJECTIVE The aim of this study is to assess the performance of the ethics committees, in the teaching hospitals affiliated with Mashhad University of Medical Sciences, in Mashhad. METHODS Subjects of this study include teaching hospitals in Mashhad, affiliated with Mashhad University of Medical Sciences and the tool used in gathering the data was a questionnaire, completed based on the information provided by the proceedings of the meetings held by the ethics committees. Also, for the purpose of gathering the suggestions, specifically on the improvement of the performance, a meeting was held with the representatives from hospitals' ethics committees. During the meeting, work reports were presented and recommendations made, based on those presentations. . RESULTS Findings of the present study suggest that all hospitals under study, have an ethics committee, of which 85.7% operate in combination with other committees. The composition of the members of the committees, in 57.1% of the hospitals, was based on the guidelines for hospital evaluation. CONCLUSIONS For the performance of the medical ethics committees to improve, it is recommended that the hospital administration and evaluation section, hold regular meetings and oblige members to participate more actively.