Larry Cohen was born on 27 March 1933 in Brooklyn, New York, and that is where he grew up. After finishing public schools in Brooklyn in 1950, he went to Harvard College in Cambridge, Massachusetts, graduating in 1954. From there, he returned to New York City to New York University School of Medicine, where he finished in 1958. He completed his internship and his first 2 years of medical residency at Yale-New Haven Medical Center in New Haven, Connecticut. In 1962, he went to Boston, Massachusetts, as a research fellow in cardiology at the Peter Bent Brigham Hospital, completing that training in June 1964, and the next month he returned to New Haven as a senior assistant resident at the Yale-New Haven Medical Center.