Diabetes mellitus is one of the most common endocrine disorders in domestic animals, particularly in cats. This chronic metabolic disease, characterized by the reduced ability of the body to regulate blood glucose levels, has multiple causes, including genetic predispositions, obesity, and hormonal dysfunctions. The etiology of diabetes can be attributed to a complex interaction of genetic and environmental factors, with obesity significantly contributing to the development of insulin resistance. In such cases, pancreatic β-cells cannot maintain adequate insulin production, leading to hyperglycemia. Understanding these mechanisms is crucial for the effective treatment and prevention of diabetes. Incretins, such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), are released in the intestines after food intake. These hormones play a vital role in increasing insulin secretion while simultaneously reducing glucagon secretion and slowing gastric emptying. In type 2 diabetes, the expression and action of incretins decrease, which affects blood sugar control. GLP-1 stimulates insulin secretion and has protective effects on β-cells, while GIP regulates lipid metabolism, which is crucial for overweight animals. The therapeutic potential of incretins is becoming increasingly clear, with the development of medications that enhance their effects. DPP-4 inhibitors and GLP-1 agonists represent promising options for treating diabetes in domestic animals. These medications improve glycemic control by reducing glucose levels and enhancing insulin secretion. Their application can improve the quality of life for animals and reduce the risk of complications associated with diabetes. Further research and clinical studies are necessary to optimize these therapies and achieve better health outcomes in dogs and cats.