The study is designed to determine the effectiveness of client-centred occupational therapy on daily functioning of patients with mild to moderate dementia in a randomised controlled trial. Patients and their primary caregivers will be treated in the participants' homes. A total of 200 patients aged > 55 with mild to moderate dementia will enter the study. 12 sessions of occupational therapy over six weeks, including client-centred interventions, based on CMOP, to train patients to compensate for decline in activities of daily living and care givers in coping behaviours and supervision. The patients in the intervention group will be compared to patients treated as usual, including drug treatment but not client-centred occupational therapy. A 3-months and a 6-month-follow-up will be performed in both groups.