['Endoscopic submucosal dissection (ESD) may be very time consuming, and depending on the anesthesia, the contents of the stomach may reflux to the esophagus and cause the patient to aspirate. To prevent these situations, many practitioners suggest using an overtube, but no study has been done to evaluate the effect of the use of an overtube while performing the ESD procedure. Our aim was to investigate the effects of performing an upper gastrointestinal ESD with and without overtube.', 'Records of patients who underwent ESD were evaluated for histopathological results, complications, speed of dissection, dosages of anesthetic medications, and number of suctions performed during the procedure. The patients were classified into two depending on whether an overtube was used or not.', 'There were a total of 58 patients on which 63 upper gastrointestinal ESD procedures were performed. Regarding age, gender, localization of the lesions, duration of the procedures, dosage of propofol, histopathological results, rate of complete resection, and rate of en-bloc resection, there was no difference between the two groups (p\xa0>\xa00,05). But the size of the lesions, the size of the resected specimen, and the speed of dissection were statistically different in two groups (p\xa0=\xa00.018, p\xa0<\xa00.001, p\xa0<\xa00.001, respectively).The need for suction during the procedure was much lower in the overtube group than those with no overtube (p\xa0<\xa00.001).'] Does the usage of overtube have a favorable effect on endoscopic submucosal dissection?