Gastrointestinal bleeding is a frequent problem and the localization of the site of hemorrhage may be a challenge. Many lines of approach have contributed information expressing the differentiation of the causes for bleeding. It was felt that the reported anatomical investigations of the problem were not extensive enough and that an additional study of an autopsy series would be enlightening. Therefore, this work was undertaken. The importance of the gastrointestinal bleeding problem is illuminated by the observation that hemorrhage as a cause of death at autopsy at the Cook County Hospital has more than doubled since a previous review of 1938.62 LITERATURE Chalmers and co-workers,11 reporting from a similar type of charity institution, stated that in 24 of 101 necropsies, fatal gastrointestinal hemorrhage was not suspected clinically. The clinical accuracy for the diagnosis of the source of bleeding was 53%. This difficulty in ascertaining site of bleeding has