Background <p>Uterine rupture in bitches is usually detected during parturition or within hours of delivery because of the deterioration of the clinical condition of the animal. In contrast, this novel report presents a confirmed case of spontaneous uterine rupture without clinical signs, which remained undetected until almost a year after natural delivery.</p> Case presentation <p>A one year and nine months old female Shih Tzu bitch gave birth to two puppies at home without veterinary assistance. The parturition took place without any apparent complications, and the female recovered well. After 8 months, the owners decided to perform an ovariohysterectomy, and a mass was found in the abdominal cavity at their local clinic, which was suspected to be a teratoma. Approximately 3 months after this surgery, the dog was presented to the authors' clinic for consultation where an ultrasonography and exploratory laparotomy were performed. The mass was found to contain three foetuses (two mummified) and signs of haemorrhage were still visible under the peritoneum. During the surgical procedure, scar tissue was found to extend throughout the uterine wall. These findings led to the diagnosis of spontaneous uterine rupture and ectopic pregnancy. Following removal of the mass and uterus, the bitch recovered well.</p> Conclusion <p>Carrying extrauterine foetuses is always associated with risks (peritonitis, septicaemia, development of teratoma, organ damage and subsequent internal haemorrhage). This case demonstrates that even if a bitch gives birth at home without any apparent complications, an ultrasound examination of the reproductive tract should be carried out after parturition.</p>