Aim: List care activities of formal and informal carers and calculate costs of care for elderly people with dementia. Comparison with those not suffering from dementia (control group) at home and in residential settings. Methods: The combined methodology of a retrospective questionnaire and a prospective diary was used to collect individual data on the use of health care (professional and informal care). Results and conclusions: For home care, we found that professional care and costs of materials does not differ in any significant way between the dementia group and the control group. Professional care was on average 5,3 hours/week. However, we did observe a clear difference with regard to the informal care. The recorded time of informal carers was significantly higher for elderly persons with dementia (on average 38 hours/week) than for elderly persons not suffering from dementia (on average 16 hours/week). In residential care facilities, the care time for dementia patients with intensive need of care (Katz score C or Cd) was almost twice that dedicated to dementia patients with slight to moderate need for care (score O, A or B on the Katz scale). However, this latter group did not differ much from the control group (predominantly score O). Therefore we conclude that the care categories indexed by the Katz scale provide, as such, an explanation for the care costs charged in the facilities. The residential setting has a great impact on care provision. The recorded time spent by nurses and carers in home care is more than twice that spent in residential facilities, despite the fact that more intensive care situations are more likely to occur in residential care. This can mainly be attributed to the presence of informal carers who provide a great deal of nursing and care tasks.