SUMMARYPurpose: Based on available epidemiologic, health economic, and international population statistics literature, the cost of epilepsy in Europe was estimated. Methods: Europe was defined as the 25 European Union member countries, Iceland, Norway, and Switzerland. Guidelines for epidemiological studies on epilepsy were used for a case definition. A bottom-up prevalence-based cost-of-illness approach, the societal perspective for including the cost items, and the human capital approach as valuation principle for indirect costs were used. The cost estimates were based on selected studies with common methodology and valuation principles. Results: The estimated prevalence of epilepsy in Europe in 2004 was 4.3-7.8 per 1,000. The estimated total cost of the disease in Europe was €15.5 billion in 2004, indirect cost being the single most dominant cost category (€8.6 billion).Direct health care costs were €2.8 billion, outpatient care comprising the largest part (€1.3 billion). Direct nonmedical cost was €4.2 billion. That of antiepileptic drugs was €400 million. The total cost per case was €2,000-11,500 and the estimated cost per European inhabitant was €33. Conclusions: Epilepsy is a relevant socioeconomic burden at individual, family, health services, and societal level in Europe. The greater proportion of such burden is outside the formal health care sector, antiepileptic drugs representing a smaller proportion. Lack of economic data from several European countries and other methodological limitations make this report an initial estimate of the cost of epilepsy in Europe. Prospective incidence costof-illness studies from well-defined populations and common methodology are encouraged. KEY WORDS: Epilepsy-Cost-of-illness-Prevalence-Europe.Epilepsy is a common and widespread neurological disorder found in all age groups and whose impact varies considerably among patients and their families, due to the disease heterogeneity in etiology, age of onset, seizure type, responsiveness to pharmacological treatment, prognosis, and comorbidity. Despite the considerable disease variability from patient to patient, the societal costs for epilepsy are overall high, due to the fairly high frequency of epilepsy in the general population. Furthermore, epilepsy is often