Background: There is little longitudinal data on resource use and costs associated with Alzheimer's disease (AD) in France.; Objectives: To evaluate resource use and societal costs associated with AD in a French cohort of patients and their caregivers and the effect of patient cognitive decline on costs over an 18-month period.; Methods: Community-dwelling patients with mild, moderate, or moderately severe/severe AD dementia (n = 419) were followed-up for 18 months.