BackgroundResearch ethics provides the ethical standards for conducting sound and safe research. The field of medical research in China is rapidly growing and facing various ethical challenges. However, in China, little empirical research has been conducted on the knowledge and attitudes of medical postgraduates toward research ethics and RECs. It is critical for medical postgraduates to develop a proper knowledge of research ethics at the beginning of their careers. The purpose of this study was to assess the knowledge and attitudes of medical postgraduates toward research ethics and RECs.MethodsThis cross-sectional study was conducted from May to July 2021 at a medical school and two affiliated hospitals in south-central China. The instrument of the study was an online survey that was distributed via WeChat.ResultsWe found that only 46.7% were familiar with the ethical guidelines for research with human subjects. In addition, 63.2% of participants were familiar with the RECs that reviewed their research, and 90.7% perceived RECs as helpful. However, only 36.8% were fully aware of the functions of RECs. In the meantime, 30.7% believed that review by an REC would delay research and make it more difficult for researchers. Furthermore, most participants (94.9%) believed that a course on research ethics should be mandatory for medical postgraduates. Finally, 27.4% of the respondents considered the fabrication of some data or results to be acceptable.ConclusionThis paper serves to suggest that research ethics education should be prioritized in medical ethics curriculum, and course syllabi or teaching methods should be revised to provide medical postgraduates with a deeper understanding of the principles, regulations, and specifics of research ethics. We also recommend that RECs provide diverse approaches in their review procedure to facilitate the understanding of medical postgraduates of the functions and processes of RECs and to enhance their awareness of research integrity.