Objective To examine the effectiveness of post-diagnosis dementia treatment and coordination of care by memory clinics compared with general practitioners. Design Multicentre randomised controlled trial. Setting Nine memory clinics and 159 general practitioners in the Netherlands. Participants 175 patients with a new diagnosis of mild to moderate dementia living in the community and their informal caregivers. Interventions Usual care provided by memory clinic or general practitioner. Main outcome measures Caregiver rated quality of life of the patient measured with the quality of life in Alzheimer's disease instrument and self perceived burden of the informal caregiver measured with the sense of competence questionnaire (intention to treat analysis). Results The quality of life of the patients in the memory clinic group was 0.5 (95% confidence interval -0.7 to 1.6) points higher than in the general practitioner group. Caregivers' burden was 2.4 (-5.8 to 1.0) points lower in the memory clinic group than in the general practitioner group. Conclusion No evidence was found that memory clinics were more effective than general practitioners with regard to post-diagnosis treatment and coordination care for patients with dementia. Without further evidence on the effectiveness of these modalities, other arguments, such as cost minimisation, patients' preferences, or regional health service planning, can determine which type of dementia care is offered.