A vaginal foreign body consisting of a piece of retained calvarium from a macerated fetus was identified and removed using vaginoscopy in a 4-year-old, spayed female bulldog. The dog had a 12-month history of chronic mucopurulent vaginitis. Vaginal foreign bodies, although uncommon, are a differential diagnosis for recurrent mucopurulent or hemorrhagic chronic vaginal discharge. A case of chronic vaginitis caused by a long-retained intravaginal foreign body in a dog is described and compared to four other canine cases reported in the literature.