Crohn's disease may involve any part of the alimentary tract, including the stomach and duodenum. We report herein the case of a 22 year-old male in whom Crohn disease was diagnosed due to weight loss in relation with a stenosis of the first and second parts of the duodenum. A gastrojejunostomy was performed with a good subsequent result. The initial management of a Crohn's disease with involvement of the duodenum is medical. When there is an indication for surgery, a gastroenterostomy is preferred, albeit with a high incidence of outlet obstruction and marginal ulceration.