BACKGROUND: Rapid demographic ageing will soon lead to large increases in the numbers of persons with dementia in developing countries. This study is the first comprehensive assessment of care arrangements for people with dementia in those regions. METHODS: A descriptive and comparative study of dementia care; caregiver characteristics, the nature of care provided, and the practical, psychological (Zarit Burden Interview, General Health Questionnaire) and economic impact upon the caregiver in 24 centres in India, China and South East Asia, Latin America and the Caribbean and Africa. RESULTS: We interviewed 706 persons with dementia, and their caregivers. Most caregivers were women, living with the person with dementia in extended family households. One-quarter to one-half of households included a child. Larger households were associated with lower caregiver strain, where the caregiver was co-resident. However, despite the traditional apparatus of family care, levels of caregiver strain were at least as high as in the developed world. Many had cutback on work to care and faced the additional expense of paid carers and health services. Families from the poorest countries were particularly likely to have used expensive private medical services, and to be spending more than 10% of the per capita GNP on health care. CONCLUSIONS: Older people in developing countries are indivisible from their younger family members. The high levels of family strain identified in this study feed into the cycle of disadvantage and should thus be a concern for policymakers in the developing world.