Canine diabetes mellitus is a common endocrinopathy, characterized by relative or absolute deficiency of the hormone insulin. Insulin is usually secreted in response to an increase in circulating concentration of glucose. Most dogs with diabetes mellitus are 5-12 years of age. Females are twice as likely to be affected than males. The clinical signs of diabetes mellitus are related to elevated concentrations of blood glucose and the inability of the body to use glucose as an energy source. The four main symptoms of diabetes mellitus are polyuria, polydipsia, weight loss, and polyphagia. Diabetes mellitus is diagnosed by the presence of the typical clinical signs, a persistently high level of glucose in the blood, and the presence of glucose in the urine. Dogs with diabetes mellitus generally require two insulin injections each day, and nutrition is an important component of disease management. In general, they must be fed the same food in the same amount on the same schedule every day. The daily routine for diabetic dogs should include exercise, preferably at the same time each day. The most common acute complications are diabetic ketoacidosis, hypoglycemia and coma, which are very fast-paced and can have a lethal outcome. Chronic complications include cataracts, uveitis, diabetic neuropathy and nephropathy, systemic hypertension, and dermatological changes