Background and Aims With the growing popularity of bariatric surgery in China, the standardization of routine preoperative examinations has become increasingly important. At present, there is some debate as to whether gastroscopic examination should be routinely performed before laparoscopic sleeve gastrectomy (LSG) or laparoscopic gastric bypass (LRYGB). This study was conducted to analyze the relationship between preoperative digestive system symptoms and gastroscopic results in patients scheduled to undergo bariatric surgery, and whether preoperative digestive system symptoms can become the basis for altering the surgical procedure, and also to compare the results between preoperative gastroscopic evaluation and postoperative pathological diagnosis, so as to determine the necessity of routine preoperative gastroscopic examination.Methods The medical records of patients who underwent preoperative gastroscopic examination prior to bariatric surgery in the Gastrointestinal Surgery/Bariatric Center of the First Affiliated Hospital of Jinan University from November 2019 to November 2021 were analyzed retrospectively. The associations of preoperative digestive system symptoms and preoperative gastroscopic findings with the alteration of surgical procedure were analyzed, and the consistency between the gastroscopic results and postoperative pathological results were determined.Results A total of 458 patients were included, with a mean age of (31.3±9.3) years and mean BMI of (38.9±7.5) kg/m². There were 103 patients (22.5%) with preoperative gastrointestinal symptoms. Among the patients, 371 cases underwent LSG and 87 cases underwent LRYGB, of whom, 82 cases (17.9%) had intraoperative changes of surgical procedures, which included hiatal hernia repair, gastric stromal tumor resection, gastric fundectomy and fundoplication in addition to the originally planned LSG or LRYGB. Four-hundred and fifty-six patients (99.6%) had abnormal preoperative gastroscopy findings, all of them (100.0%) had gastric problems such as gastritis, gastric ulcer, and gastric polyps; 53 cases (11.6%) of them had duodenal abnormalities that mainly were inflammation and ulcers; 117 cases of them (25.7%) had esophageal pathologies, which was dominated by esophagitis (94.0%). The statistical results showed that preoperative gastroscopic view was not significantly related to the presence or absence of digestive system symptoms (P>0.05); the existence of digestive system symptoms was significantly associated with the change of surgical procedure (P=0.008), which was mainly due to the significant association between the existence of digestive system symptoms and change of surgical procedure in patients undergoing LSG (P=0.008), but not due to that in patients undergoing LRYGB (P=1). Consistency analysis was performed between the preoperative gastroscopy findings and postoperative pathological diagnosis in the 370 patients undergoing LSG, and the result showed that there was no consistency between two examinations (κ=0.072, P=0.000).Conclusion Preoperative gastroscopy in patients without digestive system symptoms can help early detection of digestive diseases, and preoperative digestive system symptoms may be the basis for changing surgical procedure.