Erik De Clercq M.D. Ph.D., (1941) is a Belgian physician and biologist. He studied medicine at the Catholic University of Leuven (Leuven, Belgium). He did research and later became a professor at the Department of Medicine, where he specialised in microbiology and immunology. He worked at the Rega Institute for Medical Research. He is one of the founders and the second president of the International Society for Antiviral Research.