Churg-Strauss syndrome, or allergic granulomatous angiitis, is an uncommon vasculitic syndrome. We describe a 53-year-old man with Churg-Strauss syndrome and subsequent opportunistic cytomegalovirus enterocolitis. During intensive care, including steroid-pulse therapy, the patient developed rapidly progressive anemia caused by active bleeding from his small intestine, resulting in resection of 20 cm of ileum. Diagnosis of Churg-Strauss syndrome was confirmed both by characteristic clinical features and by histology. Histologic examination also revealed multiple shallow ulcers accompanied by cytomegalovirus infection. Characteristic angiitis was found in the ileum with normal-like mucosa, and it was not necessarily associated with ileal ulcers. This finding suggests that cytomegalovirus infection may be one of the causes or exacerbating factors for ileal ulcers in Churg-Strauss syndrome, although ulcers of the intestine have usually been considered to be caused by ischemia resulting from angiitis.