The prevalence and incidence of type 2 diabetes mellitus (DM) increase with age, and its diagnosis and treatment in older people present a challenge. Applying evidence to elderly patients can be problematic, because older persons with frailty, multiple comorbidities, and functional disabilities are generally excluded from diabetes clinical trials. Frailty is characterized by multisystem decline and vulnerability to adverse health outcomes. Insulin resistance predicts frailty, and DM accelerates muscle strength loss. Geriatric diabetes care guidelines have refocused from risk factor control to geriatric syndromes. The European Diabetes Working Party guidelines for elderly type 2 DM patients consider frailty, recommending a conservative target (hemoglobin A1c <8%). Diabetic care-home residents with physical disabilities, cognitive impairment, tube feeding, and the inability to communicate pose particular challenges. Tight glycemic control for such patients increases the risk of hypoglycemia and significant functional decline; a mean hemoglobin A1c <7% did not protect them from care-home-acquired pneumonia. In conclusion, caring for elderly diabetic patients poses unique challenges. Little is known about diabetes care of elderly people with frailty, disabilities, or multiple comorbidities. The interrelationship between frailty and DM deserves further investigation. Practice guidelines for care-home residents with DM are needed to ensure quality of care.