Vaginal pessaries still have a role in the management of uterine prolapse, particularly in elderly patients. However, they are known to cause serious complications if proper care is not taken. We present a case of a rectovaginal fistula, developing secondary to a forgotten vaginal pessary. The shelf pessary was found to have eroded through into the rectum. A review of the relevant literature was undertaken and complications associated with vaginal pessaries are discussed.