Background and Study Aims: Rising demand for general diagnostic upper gastrointestinal endoscopy in the UK is outgrowing the capacity of doctors to provide this service within a reasonable time. One solution is to train nurses to carry out the procedure, but it is not known whether nurses can perform general diagnostic upper gastrointestinal endoscopy as competently as doctors. Patients and Methods: A randomized controlled non-inferiority trial compared the adequacy and the accuracy of diagnostic upper gastrointestinal endoscopies performed by five medical and two nurse endoscopists. The videotaped procedures were assessed by a consultant gastroenterologist blinded to the identity of the endoscopist. Results: 641 patients were randomly allocated (before attendance and consent procedure) to endoscopy carried out either by a doctor or a nurse. Of these, 412 were enrolled and 367 (89%) were included in the analysis. An adequate view was obtained throughout in 53.4%(93/177) of doctor endoscopies and 91.6%(174/190) of nurse endoscopies (difference 38.2%, 95%CI 30.5%, 47.2%). In adequately viewed areas, the mean agreement between doctor and expert was 81.0%and between nurse and expert it was 78.3%(difference between the means 2.7%, 95%CL -1.0%, 6.4%). There was no difference between doctors and nurses in the rate of biopsy performance (90.4%and 91.1%, respectively, P=0.862). Nurses took longer (8.1 minutes vs. 4.6 minutes, P < 0.001) and used intravenous sedation more often (57.6%, P=0.027). Adequacy of view correlated positively with endoscopy duration (P< 0.001), but diagnostic accuracy correlated inversely with duration (P< 0.001). Neither adequacy or accuracy correlated significantly with use of intravenous sedation. Conclusions: In endoscopies performed by nurses, the proportion of adequate examinations was much higher than that found for doctors. In areas with an adequate view, there is no significant difference in accuracy between nurses and doctors. Nurses can provide an accurate general diagnostic upper gastrointestinal endoscopy service as competently as doctors. Background and Study Aims: Rising demand for general diagnostic gastrointestinal endoscopy in the UK is outgrowing the capacity of doctors to provide this service within a reasonable time. One solution is to train nurses to carry out the procedure, but it is not known whether nurses Patients and Methods: A randomized controlled non-inferiority trial comparing the adequacy and the accuracy of diagnostic upper gastrointestinal endoscopies performed by five medical and two nurse endoscopists. The videotaped procedures were assessed by a consultant gastroenterologist blinded to the identity of the endoscopist. Results: 641 patients were randomly allocated (before attendance and consent procedure) to endoscopy carried out either by a doctor or a nurse. Of these, 412 were enrolled and 367 (89%) were included in the analysis. An adequate view was obtained in 53.4% ​​(93/177) of doctor endos copies and 91.6% (174/190) of nurse endoscopies (difference 38.2%, 95% CI 30.5%, 47.2%). In fullately viewed areas, the mean agreement between doctor and expert was 81.0% and between nurse and expert it was 78.3 % (difference between the means 2.7%, 95% CL -1.0%, 6.4%). There was no difference between doctors and nurses in the rate of biopsy performance (90.4% and 91.1%, respectively, P = 0.862). Adequacy of view was positively correlated with endoscopy duration (P <0.001), but diagnostic accuracy correlated inversely with duration ((P <0.001) Neither adequacy or accuracy correlated significantly with use of intravenous sedation. Conclusions: In endoscopies performed by nurses, the proportion of adequate examinations was much higher than that found for doctors. In areas with an adequate view, there is no significant difference in accuracy between nurses and doctors. Nurses can provide an accurate general diagnostic upper gastrointestinal endoscopy service as competently as doctors.