A substantial proportion of individuals over the age of 65 years will experience some degree of cognitive impairment, and older adults with diabetes are at increased risk for these impairments. Such impairments can negatively affect activities of daily living and lead to a decrease in quality of life as well as increase caregiver burden. Cumulatively, the effects of diabetes and aging slowly diminish cognitive function, resulting in various degrees of cognitive impairment including dementia. In fact, older adults with diabetes have a 65% higher chance of developing Alzheimer disease than those without diabetes. This article reviews the synergistic effects of aging and diabetes on cognitive function. A discussion of the physiologic basis for these effects is included, in particular, the role of insulin in the brain. The final section of the article focuses on intervention strategies that can be used by nurses and allied healthcare providers to mitigate the influence of diabetes and aging so that optimal cognitive performance is maintained. Areas for future research are also discussed.