The relevance of this study lies in the necessity to evaluate the effectiveness of surgical treatment for pyometra in dogs, employing sonographic diagnosis. Pyometra, a common uterine infection in female dogs, can lead to life-threatening complications such as sepsis and kidney damage if left untreated. Ultrasound imaging, a non-invasive and effective diagnostic tool, plays a crucial role in the early detection of pyometra and can identify potential post-operative complications following ovariohysterectomy. This study aimed to identify the ultrasound characteristics of the abdominal cavity in dogs affected by pyometra and to compare the postoperative ultrasound features of the abdominal cavity following ovariohysterectomy over time in a group of animals with and without complications. The primary research method involved a sequential and targeted ultrasound examination of the abdominal cavity in dogs diagnosed with pyometra. Subsequent ultrasound examinations were performed during ovariohysterectomy and at 1, 5, and 10 days postoperatively. It was established that the pathologically altered uterus on ultrasound often exhibited characteristics of an enlarged, distended tubular structure with anechoic or hypoechoic content. Ultrasound examination of affected dogs also demonstrated diagnostic effectiveness in cases of visualising intrauterine fluid, even when the uterine size was within normal limits. The use of ultrasound diagnostics allowed for the timely detection of pyometra at early stages, significantly improving the effectiveness of subsequent treatment. Ovariohysterectomy proved to be the most effective treatment method for dogs with pyometra, promoting the normalisation of vital functions as early as 2-3 days post-surgery, which reduced the risk of recurrence. Dynamic ultrasound examination of the abdominal cavity after surgery ensured timely adjustment of treatment measures and improved prognosis for patients. The established facts have practical significance for veterinarians, which will contribute to improving the quality of pyometra diagnosis in dogs, the effectiveness of their treatment, and reducing mortality