Between 1983 and 1986 thirty-seven patients with upper gastrointestinal bleeding or stigmata of acute bleeding were treated at the Second Department of Surgery with endoscopic laser therapy. The non-contact method was used. The cause of bleeding was gastric ulcer in 13 cases and duodenal ulcer in 5. Two patients had anastomotic ulcer, 6 had a simple ulcer, 7 had telangiectases (Mb. Osler), 2 had Mallory Weiss tears and 2 bled after gastric biopsy. Twenty-one patients bled during endoscopy and 16 had signs of recent bleeding. During acute bleeding laser treatment was effective in 95% (1, 3). However, 41% of all patients (15/37) rebled within a week after laser therapy and in 30% (11/37) an emergency operation was necessary. The overall mortality rate was 10.8% (4/37). Endoscopic laser coagulation is successful in the initial treatment of acute upper GI-bleeding. However, there is a considerable risk of rebleeding. Acute laser therapy may change an emergency operation into an elective one, provided that the group at risk of rebleeding can be anticipated at first endoscopy.