Congenital uro or genito-digestive fistulas are frequently found in the context of caudal pole malformations. Isolated congenital forms without associated anorectal malformation have not been reported until now. We report the first case we know a 9 year old female child received in a pediatric surgery consultation for fecaluria evolving since birth with a permeable anus. She presented a good general condition, a good staturo-ponderal and psychomotor development, a vulva soiled by stool and a permeable anus with a tonic sphincter. A retrograde urethrocystography revealed a caeco-vesical fistula. Surgery consisted of ligation-section of the caeco-vesical septum. A follow-up urethrocystography at three months post-surgery no longer visualized the fistula. Our post-operative follow-up is 4 years. Isolated congenital caeco-vesical fistula is an unknown pathology whose late diagnosis can have serious repercussions.