BACKGROUND AND STUDY AIMS: This prospective study tested the appropriateness of referrals for upper gastrointestinal endoscopy in an open-access endoscopy unit, using the criteria of the American Society for Gastrointestinal Endoscopy. It also examined whether there was any relationship between appropriateness of use and the presence of significant lesions detected by endoscopy. METHODS: Four hundred fifty consecutive upper gastrointestinal endoscopies were studied prospectively. The referral indication was recorded by the endoscopist before the procedure was performed, and was compared with the current criteria of the American Society for Gastrointestinal Endoscopy and with endoscopic findings. RESULTS: The appropriateness of referral was assessed in 442 consecutive endoscopies. Of these, 252 (57%) were judged to be appropriate. In 168 (88%) of the 190 endoscopies rated as inappropriate, the reason was that the patient had not undergone empirical anti-ulcer therapy before endoscopy. The probability of finding a significant lesion did not differ between the endoscopies judged to be appropriate (50%) and those judged to be inappropriate (46%) CONCLUSIONS: Upper gastrointestinal endoscopy was frequently used for inappropriate indications. The main reason for inappropriate use was insufficient treatment, or no treatment, of dyspeptic symptoms prior to endoscopy. In this study, the criteria for appropriateness did not predict the probability of finding a significant endoscopic lesion.