Irun Cohen (born September 1, 1937, in Chicago, Illinois) is an immunologist at the Weizmann Institute of Science, Israel.^[1] He moved from the U.S. to Israel in 1968.

His contributions to immunology includes, in 1989, the development of the theory of the immunological homunculus, a hypothetical self-image used by the immune system to govern its responses. The bulk of Professor Cohen's work is in the search for treatment for autoimmune disease.^{[citation needed]} Throughout his career he has collaborated with scientists of all nationalities, including the Cuban immunologist Enrique Montero.^{[citation needed]} Cohen is currently the Israeli scientist with the second (first is Leo Sachs) largest number of publications in the journals of Science and Nature.^{[citation needed]}

Cohen studied philosophy at Northwestern University obtaining a Bachelor of Arts in 1959. He studied medicine at Northwestern Medical School obtaining a degree in medicine in 1963.^[2]

• "Irun Cohen: Executive Profile & Biography". BusinessWeek.com. Bloomberg. Archived from the original on October 13, 2012. Retrieved 3 June 2011.