The economic and social burden of dementia on society is the Value of all the resources used to prevent, diagnose, treat, and generally cope with the illness. There is increasing pressure to define the con components of dementia with a view to improving resource allocation and accountability in this area in the Future. We have assessed the overall resource implications of dementia in Ireland. Six main areas are covered in the cost analysis as follows: mortality and life years lost, in-patient acute care, in-patient psychiatric care, residential long-slay care, family care, and primary and social care in the community. While the results indicate that the baseline cost of illness associated with dementia is substantial at just under IR pound 250 million, the most important aspect of the work is the distribution of the burden, The critical role of carers in maintaining people with dementia in their own home is reflected in the results showing that family care accounts for almost 50% of the overall resource burden, based on an opportunity cost valuation of carer time. Copyright (C) 2000 John Wiley & Sons, Ltd.