Ulcerative colitis (UC) is a chronic inflammatory disease of the colon of unknown etiology. There are varied manifestations in the natural course of UC. However, duodenum is not generally considered a target organ of UC. Here, we report two patients with steroid-responsive ulcerative duodenitis with colitis that was consistent with UC, but not with Crohn's disease. We also reviewed six cases of ulcerative duodenitis with UC. Duodenal lesion with UC may be a more common phenomenon, although infrequently clinically manifested under steroid therapy. Upper gastrointestinal tract inflammation in UC warrants further studies to ascertain whether the duodenum is a target organ in UC, especially in steroid-free conditions.