Yihai Cao, M.D., hM. D., Ph.D., (born October 29, 1959) is a Chinese-born Swedish scientist and a professor at the Karolinska Institute, Sweden.

He is also an honorary professor/guest professor in Copenhagen University, Denmark; Linköping University, Sweden; Leicester University, UK; Shinshu University, Japan; Shandong University, China; and Peking University, China.

He is an internationally recognized and cited researcher in cancer, obesity, diabetes, cardiovascular disease, and eye disease research. His publications have been cited more than 35000 times and his h-index is 92.

Cao received the Fernström research prize, the Karolinska distinguished professor award, and the Axel Hirsch Prize in medicine.

Cao received an ERC-advanced research grant award, and a Novo Nordisk-advanced grant award.

From 2018, Cao was elected to Academia Europaea, the European Academy of Sciences and Arts, the Chinese Academy of Engineering, the National Academy of Inventors, and The World Academy of Sciences.

His research findings received broad public attentions including New York Times, Reuters and Swedish National TV broad casting.