In the late post-operative period, the necessity of performing an upper gastrointestinal endoscopy (GIE) to check for complications is controversial. Some authors suggest it should be routine for all patients, others selectively, but not all patients with endoscopic abnormalities are symptomatic and some abnormalities are potentially severe. The study was conducted to evaluate the endoscopic findings from asymptomatic obese patients after Roux-en-Y gastric bypass (RYGB) and correlate them with the demographic data and the presence of Helicobacter pylori (Hp). A total of 715 asymptomatic patients were prospectively submitted to an upper GIE at the end of their first post-operative year. These examinations were evaluated for the presence of abnormalities, their prevalence and their potential severity. Abnormalities were found in 189 patients (26.5 %). Eighty-four (11.7 %) presented esophageal abnormalities, with 72 (10.1 %) characterized as esophagitis and 12 (1.7 %) as hiatal hernia. Forty-five patients (6.3 %) presented abnormalities of the stomach and the anastomosis, with 26 (3.6 %) characterized as anastomotic ulcers, nine (1.3 %) as stenosis of the gastrojejunal anastomosis, ten (1.4 %) as band erosion and 72 (10.1 %) as jejunitis. There was a statistically significant correlation between super obesity and band erosion. An upper GIE at the end of the first year of RYGB plays an important role, even for asymptomatic patients. One fourth of these asymptomatic patients had their treatment modified after the upper GIE was performed.