Dementia describes when a person has cognitive limitations that impede function. Persons with kidney disease are unduly impacted by dementia: up to 87% of the dialysis population has cognitive impairment. In this review, we discuss the diagnosis and management of dementia, including the role of cerebrovascular disease and other risk factors. We review the available screening tools for the diagnosis of dementia. We discuss how the diagnosis of dementia differs from the diagnosis of mild cognitive impairment, and also detail how delirium and depression can mimic dementia.