Doctors are optimistic in their perception of how acceptable endoscopy is for patients. We analyzed elements that contribute to a poor experience for the patient and the agreement between the perceptions of endoscopists and patients. Eighty-four out-patients who had undergone gastroscopy completed questionnaires (response rate of 73%) 48 to 96 hours after the procedure. The endoscopist completed a similar questionnaire. Questions concerned overall tolerance, swallowing, retching and vomiting, sedation, duration, diagnosis, age, and sex. Data from both doctor and patient were available in 84 cases. The type of sedation, administration of hyoscine or Xylocaine (Astra Pharmaceuticals Ltd., Kings Langley, UK), diagnosis, and expression of need for more sedation were not statistically significantly related to the overall patient score. The largest contribution to a poor overall tolerance score arose from difficulty in swallowing the endoscope, followed by the duration of the procedure. A total of 8.3% of patients reported some overall difficulty which was not recognized by the endoscopist. In relation to retching and vomiting, 11.9% of patients had difficulty with retching and vomiting, which went unrecognized by the doctor, and 18% had difficulty in swallowing the endoscope. There was fair agreement between the assessments of overall acceptability of both endoscopists and patients. Difficulty in intubation, however, is the major contributor to a poor tolerance of gastroscopy and also the issue on which doctors and patients disagreed the most.