In the English literature, only 27 cases of arterial thrombosis associated with Crohn's disease have been described. The present case appears to be the first reported case in the Japanese literature. A 43-year-old man was treated for intestinal obstruction caused by Crohn's disease and complicated by superior mesenteric vein thrombosis by surgical resection of 150cm of small bowel in June 1981. In March 1983, the right external iliac artery had become occluded and part of the left external iliac artery had assumed an irregular shape and the right ilio-femoral bypass surgery using PTFE was carried out. Three months later occlusive ileus reoccurred and angiograms showed that the superior mesenteric and right hepatic arteries had 30% and 20% stenosis respectively. Small bowel in 50cm in length was resected with subsequent administration of salicylazosulfapyridine at a dose of 3g per day. There was no reappearance of bowel symptoms. The patient again complained of numbness in the right leg in February 1988 and a left external iliac-right common femoral crossover bypass operation was carried out using a ringed 8mm Dacron graft. Intraoperatively, it was found that the left external iliac and the right common femoral arteries had intimal thickening but no atherosclerosis.