This article presents the data on cost of the major brain disorders in Belgium which were retrieved from "Cost of Disorders of the Brain in Europe" study sponsored by the European Brain Council and performed by Stockholm Health Economics. The disorders selected were: addiction, depression, anxiety disorders, brain tumours, dementia, epilepsy, migraine and other headaches, multiple sclerosis, Parkinson's disease, psychotic disorders, stroke and trauma. Figures for prevalence of disorders and direct medical, direct non-medical and indirect costs are based on data coming from available electronic data bases, or when missing for Belgium, best possible estimates or extrapolated data were used. All economic data were transformed to Euro's for 2004 and adjusted for purchasing power parity (PPP). The results show that the total number of people with any brain disorder in Belgium amounts to 2.9 million in 2004, the most prevalent being anxiety disorders 1.1 million, migraine 860000, addiction (any) 800,000 and depression 500,000 cases. The total cost of all included brain disorders in Belgium was estimated at 10.6 billion Euros. Most costly per case are brain tumours, multiple sclerosis, stroke and dementia. Because of their higher prevalence, however depression, dementia, addiction, anxiety disorders and migraine have the highest total costs. Taken together brain disorders consume 4% of the gross national product and cost each citizen of Belgium 1029 Euros per year. The drug costs for brain disorders constitute only 10% of the total drug market in Belgium, and only 4% of the total cost of brain disorders in Belgium. This should be compared to the cost estimates and to a previous study which showed that brain disorders are responsible for 35% of the total burden of all disorders in Europe. This study suggests therefore that the direct healthcare resources, including expenses for drug therapies, allocated to brain disorders in Belgium are not leveled to the indirect costs and burden of these disorders. A comparison with data available from a direct prospective study in demented Belgian patients suggests that the mathematical estimates presented here reflect quite accurately the real average cost for dementia, although there are large variations depending on disease severity. As, in addition, subjects with brain disorders face collateral costs which have not been taken into associations, a complementary survey in the Belgian ecosystem to establish the cost profile of representative patients for the major brain disorders. Such a survey is being organized by a task force of the Belgian Brain Council.