End-stage renal disease (ESRD) is a common condition observed in the elderly. Ageing represents one of the main risk factors of the disease, in addition to hypertension and diabetes. ESRD can require the initiation of dialysis, which is a costly and complex strategy, particularly for patients aged 80 years or more. When the decision to initiate dialysis is being made by nephrologists, many parameters should be simultaneously considered to evaluate potential benefits for the patient, such as life expectancy, functional independence and, of course, quality of life. This decision-making process could be improved if comprehensive geriatric assessment were performed. Cognitive function and more particularly, a medical history suggesting dementia (which can be misdiagnosed in 50% of demented patients) must be carefully investigated. Indeed, ESRD and dementia share several risk factors such as ageing, but in addition, dementia may negatively impact on weekly dialysis programs and survival of treated patients.