Aim: Open access endoscopy allows physicians and general practitioners (GIs) to refer patients for endoscopy without prior outpatient consultation. This system was introduced to reduce waiting time to the procedure and subsequent diagnosis. Concerns have been raised regarding misuse of this system with increasing number of inappropriate referrals and hence more normal examinations, which has implications on a public-funded health system. The aim of this study was to assess the appropriate use of the open access system at a rural New Zealand hospital and to see if the diagnostic yield improves by following the American Society of Gastroenterology (ASGE) guidelines for upper gastrointestinal endoscopy [esophagogastroduodenoscopy (OGD)]. Materials and methods: This was a prospective study including all the patients who had OGD at Taranaki Base Hospital between December 2013 and 2014. A total of 1,019 patients had OGD during this time period. The ASGE guidelines were used to see the relationship between appropriateness of OGD and finding of a relevant endoscopic diagnosis. Results: Fifty-eight percent of the OGDs were judged to be appropriate and 42% inappropriate by the explicit criteria. No cancer was found in OGDs judged to be inappropriate. Upper gastrointestinal (GI) endoscopies judged appropriate yielded significantly more relevant lesions than those judged to be inappropriate [65% vs 32%; odds ratio 3.94, 99% confidence interval (CI) 2.78, 5.57; p < 0.01]. Conclusion: The use of ASGE guidelines increases diagnostic yield of OGDs done, which is crucial to cost-effectiveness of an open access system and makes the system more efficient in selecting and treating patients who need it the most, in an acceptable time span.