Baruj Benacerraf (1920 - 2011) was a Venezuelan-American immunologist, who shared the 1980 Nobel Prize in Physiology or Medicine for the "discovery of the major histocompatibility complex genes which encode cell surface protein molecules important for the immune system's distinction between self and non-self." In 1968, he became chief of the immunology laboratory at the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland. From 1970 to 1991 he served as both professor of comparative pathology and chairman of the pathology department at Harvard University Medical School. He also was president (1980-91) of the Sidney Farber Cancer Institute (now the Dana-Farber Cancer Institute) in Boston. Benacerraf was elected to the National Academy of Sciences (1973) and was awarded the National Medal of Science (1990).