Born in Urmia, Persia on 2 September 1881 he graduated from Columbia University, New York in 1908 and subsequently became Valentine Mott Professor of Surgery there at the College of Physicians and Surgeons. He served throughout his career on the staff of the Presbyterian Hospital, New York and was Director of the surgical service 1921-46. He was also clinical director of the Memorial Hospital. During the second world war he was a consultant with the American forces in England and North Africa, and was chairman of the US National Research Council's committee on infected wounds and burns. After retirement he became a consultant adviser at Princeton University to undergraduates seeking medical careers. He had been chairman of the American Board of Surgery, President of the Society for Clinical Surgery and President of the New York Surgical Society. He devised "Whipple's operation" for cancer of the pancreas by radical excision of the ampulla of Vater and did valuable research into cancer of the biliary tract (*Annals of Surgery* 1935, 101, 1299 and 102, 763, and *American Journal of Surgery* 1938, 40, 260). He received many awards, and the Allen O. Whipple Surgical Society was formed in his honour in 1952. He had practised at 444 East 68th Street, New York, later lived at Princeton, New Jersey, and died on 16 April 1963 aged 81.