Appendico-vesical fistula is a rare condition. In total, 109 cases, most secondary to appendicitis, have been reported in the English-language literature. We report the first case, to our knowledge, of appendico-ileo-vesical fistula secondary to appendiceal diverticulitis. An enterovesical fistula was diagnosed by urine culture, cystoscopy, and computed tomography. The locations of enteric opening sites were demonstrated by barium enema and colonoscopy. Ileocecal resection and fistulectomy with primary reconstruction were performed. We believe that accurate pre- and intra-operative diagnosis is essential for cure. This case demonstrates the importance of barium enema and colonoscopic examinations in the diagnosis and treatment of complicated enterovesical fistula.