OBJECTIVE to study the incidence of hospitalisation, causes, and outcomes of acute upper gastrointestinal bleeding (AUGIB) in southern Saudi Arabia. METHODS prospective study of patients admitted with AUGIB to a large district hospital in Abha City, southern Saudi Arabia, between 1991 and 1993. All patients had upper endoscopy within 24 hours of admission. RESULTS AUGIB was the indication for upper endoscopy in 240 (8.9%) of all upper gastrointestinal endoscopies (2,702). The patients' mean age was 44.3 years (SD 18.1; range 20-85 years). The annual hospital admission rate for AUGIB was calculated as 31 per 100,000 population over the age of 20. The commonest causes were oesophageal varices (30%), gastritis and erosions (25%) and duodenal ulcers (22%); gastric ulcers and malignancy were relatively uncommon. Liver cirrhosis due to hepatitis B and C viruses was the main cause of bleeding oesophageal varices. Patients with variceal bleeding were younger and had a higher mortality rate than non-variceal bleeders. CONCLUSIONS bleeding oesophageal varices are the commonest cause of AUGIB in Saudi Arabia owing to the endemicity of viral hepatitis B and C. The mortality from both variceal and non-variceal bleeding was lower than in western countries probably because the patients are younger and because of the relative rarity of malignancy and of the consumption of non-steroidal anti-inflammatory drugs.