Diabetes mellitus has large share in morbidity and mortality of the world's population, and presents one of the biggest health challenges of nowdays. The disease affects almost every organ system in the body, including the skin. Cutaneous manifestations in patients with diabetes are numerous and various. They can be classified into four major groups: cutaneous manifestations of diabetes, cutaneous infections, cutaneous manifestations associated with diabetes and cutaneous complications of diabetes therapy. Complex pathogenesis of these skin changes is result of the interaction of several factors, most important of them being hyperinsulinemia and nonenzymatic glycation of cutaneous structural proteins. Cutaneous manifestations of diabetes mellitus include necrobiosis lipoidica diabeticorum, disseminated granuloma annulare, diabetic dermopathy, bullosis diabeticorum, xanthosis and diabetic thick skin syndrome. Cutaneous infections in diabetic patients can be bacterial or fungal. Skin conditions that are associated with diabetes are acanthosis nigricans, pruritus, vitiligo, psoriasis, lichen planus and others. Skin changes due to diabetes treatment may occur with the use of insulin or oral antidiabetics. Skin changes can be the first sign of diabetes, or they can occur later in the course of the disease. Some of them can lead to severe complications. It is important to recognize and treat them appropriately as soon as recognized.