Roger Charles Louis Guillemin (born 11 January 1924 in Dijon, Côte-d'Or, France) received the National Medal of Science in 1976, and Nobel Prize in Physiology or Medicine in 1977 for his work on neurohormones.
Completing his undergraduate work at the University of Burgundy, Guillemin received his M.D. degree from the Medical Faculty at Lyon in 1949, and went to Montréal, Québec, Canada to work with Hans Selye at the Institute of Experimental Medicine and Surgery at the Université de Montréal where he received a Ph.D. in 1953. The same year he moved to the United States to join the faculty at Baylor College of Medicine at Houston. In 1965, he became a naturalized citizen of the United States. In 1970 he started a laboratory, San Diego where he worked until retirement in 1989.
Guillemin and Andrew V. Schally discovered the structures of TRH and GnRH in separate laboratories.