en Bariatric Surgery Bariatric Surgery Original Original <strong>Background</strong>: The aim of this study was to evaluate the prevalence of H.pylori, before and one year after Roux-en Y gastric bypass surgery.<br> <strong>Method:</strong> The laparoscopic research center database from 2018 to 2020 was queried to identify patients undergoing laparoscopic Roux-en Y gastric bypass surgery(LRYGB). Retrospectively, the patients were evaluated for the presence of H.pylori infection via endoscopy or H. pylori Stool Ag before and 1 year after the surgery.<br> <strong>Results: </strong><a name="_Hlk63551460">Among the 106 patients, H.pylori was positive in 50 (47.2%) patients pre-operatively. Based on post-op evaluation among 54 patients, only 4 (7.4%) developed post-op H.pylori infection. </a><br> <strong>Conclusion:</strong>. eradicating H. pylori in patients under Roux-en Y gastric bypass surgery remains efficient. So, it is not recommended to re-checked H.pylori Ag in patients after Roux-en Y gastric bypass surgery in the short term; but, further studies are suggested to evaluate the need for re-screening patients for H.pylori Ag in the long term after Roux-en Y gastric bypass surgery<br> <strong>Keywords: </strong>Helicobacter Pylori; Iran;LRYGB; Helicobacter pylori, Iran, laparoscopic Roux-en Y gastric bypass surgery (LRYGB) 27 30 http://annbsurg.iums.ac.ir/browse.php?a_code=A-10-34-4&slc_lang=en&sid=1 Sadra Valiee Sadravaliee@gmail.com 10031947532846001929 10031947532846001929 No Laparoscopy Research Center, Department of Surgery, School of Medicine Shiraz University of Medical Sciences, Shiraz, Iran. Babak Hosseini babak1380@gmail.com 10031947532846001930 10031947532846001930 No Laparoscopy Research Center, Department of Surgery, School of Medicine Shiraz University of Medical Sciences, Shiraz, Iran. Masood Amini amini.mas2018@gmail.com 10031947532846001931 10031947532846001931 No Laparoscopy Research Center, Department of Surgery, School of Medicine Shiraz University of Medical Sciences, Shiraz, Iran. Neda Haghighat neda.hag@gmail.com 10031947532846001932 10031947532846001932 No Laparoscopy Research Center, Department of Surgery, School of Medicine Shiraz University of Medical Sciences, Shiraz, Iran. Hamidreza Hosseinpour Hp_hamid@gmail.com 10031947532846001933 10031947532846001933 No Laparoscopy Research Center, Department of Surgery, School of Medicine Shiraz University of Medical Sciences, Shiraz, Iran. Nader Moeinvaziri nmv1986@yahoo.com 10031947532846001934 10031947532846001934 Yes Laparoscopy Research Center, Department of Surgery, School of Medicine Shiraz University of Medical Sciences, Shiraz, Iran. Reza Shahriarirad R.shahriari1995@gmail.com 10031947532846001935 10031947532846001935 No Thoracic and Vascular Surgery Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran Ali Shahabinezhad Ali.shn71@yahoo.com 10031947532846001936 10031947532846001936 No Laparoscopy Research Center, Department of Surgery, School of Medicine Shiraz University of Medical Sciences, Shiraz, Iran. Sepehr Shahriarirad shahriari77.s@gmail.com 10031947532846001937 10031947532846001937 No Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran