The patient was a 40-year-old man who had suffered from Crohn's disease (CD) for 19 years and developed an intractable perianal fistula and two strictures in the small bowel. Dilatation of the two strictures using double-balloon endoscopy did not improve the subileus symptoms. An anal canal adenocarcinoma was also detected using double-balloon endoscopy. The ileum and rectoperianal area were partially resected, and a precise immunohistochemical pathologic assessment revealed that all three lesions were fistula-associated adenocarcinomas. Accumulating endoscopic findings of CD-associated cancer and precise pathologic diagnostic findings will help to establish a suitable surveillance method.