To evaluate the prognostic value of the endoscopic examination, we included 189 consecutive patients with upper gastrointestinal bleeding, in a prospective study. Rebleeding was more frequent in patients with endoscopic stigmata of hemorrhage. The prognostic prediction given by the physician was slightly, but not significantly, improved after the result of the endoscopy was available. However, when the clinical data were evaluated by computer, using the Bayes' theorem, the endoscopic findings provided no additional prognostic value. We conclude that the endoscopic findings have intrinsic prognostic value, but add little to clinical data obtained on admission.