Congenital biliary tree malformations are rarely described in the veterinary field. A congenital umbilicobiliary fistula associated with gallbladder agenesis was reported here for the first time in a 1-year-old male French bulldog. After contrast study, abdominal ultrasound, and histopathology, we concluded that the umbilicobiliary fistula was an aberrant duct that originated directly from the expected location of the cystic duct and gallbladder. The clinical case was treated surgically through ligation and excision of the aberrant duct before entering the common bile duct. The recovery and long-term follow-up were uneventful. The pathophysiology of biliary congenital malformations is discussed, along with clinical considerations that should be considered in similar future cases.