A common late complication after gastric bypass surgery is marginal ulceration that is defined as ulcers at the margins of the gastrojejunostomy, mostly on the jejunal side. Its incidence after RYGB ranges from as low as 0.6 to as high as 16%. After 1,040 laparoscopic RYGB surgeries, the incidence rate, in our hands, is 1.4% and mainly related to NSAID´s use. In observational cohort studies, the presence of specific technical factors - staple-line dehiscence or gastro-gastric fistula, enlarged pouch, foreign material and local ischemia - and environmental factors - tobacco, NSAID´s, alcohol consumption, and H pylori infection among others - have been associated with marginal ulceration however the exact etiopathogenesis has not been completely elucidated.