Peter I. Jatlow, M.D., 84, passed away at his home peacefully on Monday, May 18, 2020 after a long illness. Dr. Jatlow served as Chair of the Department of Laboratory Medicine at Yale School of Medicine from 1984-2006. Mostly recently, he was Professor Emeritus of, and Senior Research Scientist in, the Departments of Laboratory Medicine and Psychiatry. His clinical interests were focused on clinical chemistry and toxicology. His research activities were primarily concerned with the clinical pharmacology of drugs of abuse, including nicotine and alcohol and he published some of the earliest studies of the clinical pharmacology and pharmacokinetics of cocaine. A fellow of the American Institute for the Advancement of Science, he was the author of more than 100 publications and was recognized with numerous awards and honors. Dr. Jatlow was born in New Brunswick, New Jersey and grew up in Mount Vernon, New York. He received his B.S. from Union College in 1957 and his M.D. in 1961 from the State University of New York, Downstate Medical Center. After a mixed medicine-surgery internship at Montefiore Hospital in Bronx, New York, Dr. Jatlow spent four years as a resident and postdoctoral trainee in pathology and laboratory medicine at Yale-New Haven Hospital and Yale School of Medicine. From 1966 to 1968, Dr. Jatlow was in the U.S. Public Health Service, where he set up the first pathology department for the Alaskan Native Medical Center in Anchorage, Alaska. In 1968 he returned to join the faculty of Yale School of Medicine where he remained for the balance of his career. Dr. Jatlow had a green thumb and enjoyed tennis and travelling with his family. He collected fountainpens and enjoyed wine and a good meal. He loved the outdoors and particularly enjoyed exploring the Four Corners region of the American Southwest and hiking the trails of Acadia National Park. He is survived by his beloved wife, Stephanie, two daughters, Allison Beitler and Julie Guilmette, two sons-in-law, Richard and Keith, and by his three grandsons, Gordon, Brian and Daniel. In lieu of flowers, donations may be made to the Connecticut Food Bank at www.ctfoodbank.org/ways-to-give or send 2 Research Pkwy, Wallingford, CT 06492-1929