The spread of oncological diseases is currently one of the main problems in both humanitarian and veterinary medicine. Despite the high achievements of domestic and foreign scientists of modern veterinary medicine in the field of diagnosis, treatment and prevention of oncological processes, the number of cancer-affected animals is quite large and continues to grow steadily. Therefore, improving the complex of diagnostic studies for neoplasms among dogs and cats is one of the priority areas of veterinary medicine. The research was conducted on the basis of the veterinary clinic of the Center for Animal Beauty and Health "Zoostyle" IP Gorinsky V.I. (Volgograd) and the Department of "Morphology, Pathology of Animals and Biology" of the Saratov State Agrarian University. In the period from 2018 to 2021, 244 patients, including 127 dogs and 117 cats, were examined by an oncologist at the veterinary clinic of the Zoostyle Center for Animal Beauty and Health.All the animals belonged to residents of the city of Volgograd. When an animal was admitted to the clinic for an oncological appointment, animals with any visual signs of a neoplasm in the projection of the breast were selected for research. As a result of the physical examination, based on the results of laboratory, X-ray and ultrasound examinations, MR tomography, it was found that breast tumors (OMJ) are more common among dogs and cats. In the population of dogs, OMH accounted for 33.8% (n=43) and 62.4% (n=73) of all cases of oncological pathology in cats. Depending on the gender, breast neoplasia was observed in females - 100%, in cats, females accounted for 89%, and males - 11%. The results obtained indicate that the introduction of a complex of modern high-tech diagnostic methods into veterinary oncology practice is a key element that significantly affects the prospects for providing specialized care and prognosis.