Seymour Stanley Cohen (April 30, 1917-December 30, 2018) was an American biochemist. Cohen was born in Brooklyn, New York in April 1917. He attended City College of New York and his PhD came from Columbia University under the supervision of Erwin Chargaff. In the 1940s he worked on plant viruses and for the Rockefeller Institute.[1] He was awarded a Guggenheim Fellowship in 1945.[2] He is known by his studies with marked of radioactive isotopes, whose results suggested an essential role of DNA in hereditary genetic material. This result would be checked in 1952 by Hershey and Chase.[3][4][5]