Background: Obesity is considered now in the twenty first century one of the major health problems that affect many aspects of individual’s health. Morbid obesity is believed to be the second leading cause of preventable death behind cigarette smoking. Laparoscopic Mini Gastric bypass (LMGBP) is increasingly performed for morbidly obese patients and has recently gained popularity and acceptance as an effective procedure for the treatment of morbid obesity and improvement of obesity-related comorbidities. Safety and satisfactory short and long term outcomes of LMGBP have been reported in large series. A high incidence of biliary gastritis of around 70% after Mason’s old loop gastric bypass has been reported. This has resulted in increased use of Roux-en-Y reconstruction in the performance of gastric bypass. Aim of work: This study was conducted to evaluate the incidence of biliary gastritis following LMGBP and to figure out the association of H. pylori with the occurrence of postoperative gastritis. Methodology: This pilot study included 20 patients. All of them underwent a LMGBP as a primary one-stage bariatric procedure in kasr Alaini university hospital, general surgery department, faculty of medicine, Cairo University in a period of 12 months, from January 2015 to January 2016 with a follow up period of 6 months. All 20 patients had an upper GI endoscopy done at 6 months postoperative. Gastric aspirate was obtained to assess bilirubin level. Gastric and esophageal biopsies were taken and submitted for histopathology and campylobacterlike organism CLO test. CLO test was done selectively on preoperative endoscopy for patients with positive endoscopic findings. Results: Endoscopy findings at 6 months postoperative: Nine patients out of twenty had normal gastric and esophageal mucosa. Mild gastritis and esophagitis were evident in 9 patients. Severe esophagitis, gastritis with ulcers, polyps and erosions appeared in 2 patients. Gastric biopsy confirmed endoscopic findings in 12 patients who had normal mucosa or evidence of mild gastritis. 8 patients had moderate to severe gastritis (2 of them had erosions and metaplasia on top). There was no relationship of statistical significance between results of H.pylori test and the findings of histopathological examination of gastric biopsy with a P value of 1.0. This study highlighted the safety of MGBP in our Hospital setting. No mortality, low morbidity with quick postoperative recovery. Incidence of biliary gastritis was 6/20 (30%).Conclusion: The rate of biliary gastritis post LMGBP needs more studies on larger sample size with longer follow up period for proper assessment of incidence of biliary gastritis and association with H.pylori. Keywords: Mini Gastric bypass - Biliary gastritis – H.Pylori.