Saul L. Cohen was born on May 23, 1913 to Esther and Israel Cohen, in Regina, Saskatchewan. Cohen's family moved to Brandon, Manitoba in 1917 where his father ran a junk business and his mother ran a grocery store. Cohen attended primary and secondary school in Brandon, and also attended Brandon College from 1928-1932. In 1932, Cohen moved to Toronto where he attended the University of Toronto from 1932-1936, and graduated with his Ph.D. in Biochemistry. Cohen then moved to Switzerland to work for one year. Upon returning to North America in 1937, Cohen moved to Columbus, Ohio where he lived and worked until 1942. On June 12, 1938, Cohen married Miriam Weinstein, originally of Melita, Manitoba. From 1942-1946 Cohen worked in Ann Arbor, Michigan. In 1946 Cohen moved to Minneapolis, Minnesota, where he stayed until 1956. In 1956, the Cohens finally moved back to Toronto, where they lived until 1985. Cohen and his wife had three children, Suzie, Judy, and David.