OBJECTIVES: Given the national interest in progressive dementia, we estimated expenditures incurred in caring for dementia patients who live at home. METHODS: Primary caregivers of 264 patients from a university-based memory disorders clinic were interviewed at baseline and asked to keep service use diaries for 6 months; 141 caregivers who returned the diaries are the focus of this report. We examined both formal and informal services (distinguished by whether money was exchanged) and associated expenditures. RESULTS: Neither caregivers returning diaries nor their patients differed at baseline from those not returning diaries and their patients. Expenditures incurred over 6 months were extensive for both formal ($6986) and informal ($786) services. Out-of-pocket expenditures were high (e.g., in-home companion or sitter, adult day care, visiting nurse). Multivariable analyses indicated that patients with more severe symptoms of dementia and families with higher incomes reported significantly higher expenditures. CONCLUSIONS: The expense of caring for patients with progressive dementia living at home may be higher than previously estimated and frequently involves expenses paid directly by patients and their families.