Arterial thrombosis is a rare complication of ulcerative colitis with many difficulties in its treatment. The pathogenesis of thrombosis is not well known and many factors are implicated such as elevated fibrinogen, increased platelet count, and decreased antithrombin III levels. We report a case of a 43-year-old man with ulcerative colitis and sudden and refractory thrombosis of the brachial and radial artery. Despite efforts to restore the blood flow, the final and effective means was the resection of the large bowel.