The most frequently occurring type of dementia is Alzheimer's disease. Alzheimer's disease is a degenerative illness affecting the brain, decreasing the patient's memory and judgement. A cure is not available but it is possible to delay the cognitive decline with medication. New drugs like Aricept and Metrifonate appear to have no or minor side effects and have a positive effect on the cognitive functions and behavior of the patient. At this moment the iMTA is studying the cost-effectiveness of Metrifonate. This thesis is part of that study and focuses on the costs of Alzheimer's disease. The main question formulated in this thesis was: How do the costs of institutionalization compare with the costs of living at home for patients with Alzheimer's disease in The Netherlands and France? For The Netherlands earlier studies on the use of health care services by demented patients were used to estimate the costs for demented patients living at home. These costs depend on the amount of formal and informal health care services that demented patients use. The valuation of informal care also determines the amount of costs for patients living at home. The costs of living at home were compared with the costs of institutionalization. The costs of demented patients liv