Diabetes mellitus is a common disease in older people, with almost 50 % of Type 2 diabetic patients being over 60 years of age; despite this, half of older people with frank diabetes are not diagnosed. While insulin resistance is common in older people, large numbers also have impaired insulin secretion. Age, body habitus and physical activity all play a role in the pathogenesis of hyperglycaemia associated with diabetes mellitus. Leptin levels relate to insulin resistance in older people and amylin secretion is associated with delayed return of glucose levels to baseline. Depression, impaired cognitive function, and lack of recognition of thirst and subsequent dehydration are important factors to be taken into account in the management of older diabetic patients, who may also have impaired physical function, an increased rate of injurious falls, and increased prevalence of pressure ulcers, amputations and tuberculosis. Hyperglycaemia can result in a decreased pain threshold and incontinence. Dietary management plays less of a role in older diabetic patients but exercise, with a particular emphasis on balance and stability, is an important component of the management and treatment of older diabetic patients. The use of metformin as a treatment should be avoided in patients over 80 years of age because of declining kidney function. Insulin therapy is an option but as hypoglycaemia is related to advancing age, patients should be monitored carefully for the development of hypoglycaemia. Care providers also play an important role in the management of older people with diabetes mellitus. Glycaemic control can be obtained with minimal side-effects in most older diabetics including those patients in nursing homes.