OBJECTIVE: to assess the impact of dementia and its severity on mental health, physical health and social functioning of caregivers of elderly people living at home. METHODS: Study population : 181 caregivers of subjects aged > 65 with mild (D1), moderate/mild (D2), moderate (D3) or severe dementia (D4), 118 caregivers of non demented subjects aged > 65 with (R2) or without (R1) cognitive disorders. Generic quality of life (QOL) was assessed with COOP/WONCA and SF-36 measures. Depression was assessed using Beck Depression Inventory (BDI). Medications were registered. RESULTS: COOP/WONCA charts showed marked impairment of social activities for caregivers of D3 patients (mean score: 2.6 versus 1.8, 2.1, 1.9, 1.9 and 1.5 for caregivers of respectively D1, D2, D4, R2 and R1 subjects). Small differences appeared in the other functional aspects. SF-36 showed comparable mean Physical Component Scores (PCS) for all caregivers, ranging from 43.5 to 46 according to cohort. Caregivers of D3 and/or D4 patients tended to have lower scores in scales assessing Role limitations due to Physical problems, Bodily Pain and General Health. Mean Mental Component Scores (MCS) had the lower values for caregivers of D3 (42.0) and D2 (44.7) patients and the highest value for caregivers of R1 subjects (50.9). Caregivers of D3 patients had the lowest scores in scales used to score the MCS, namely Social Functioning, Emotional role, Mental Health and Vitality. More than 60% of caregivers of D3 patients suffered from depression versus 30% of caregivers of R1, R2 or D1 subjects and 43% of caregivers of D2 or D4 patients. Results on correlation with medications and association with cohabitation status, age and gender will be presented. CONCLUSION: moderate/mild to severe dementia has an impact on mental health, physical health and social activities of caregivers. The impact appears particularly important for caregivers of moderately demented patients (MMSE 10-14).