Rare diseases have become an issue of public health concern globally. In China, two rare diseases lists have been released officially in 2018 and 2023, respectively. However, due to its importance in research, clinical management , therapeutic drug development and health security, we still need a clear definition of rare diseases in China. Considering the current actual condition of our country and our population size, we would suggest a prevalence of less than 1/10 000 to define a rare disease in China.