OBJECTIVES: To estimate the socio-economic cost and health-related quality of life (HRQL) for adults with partial epilepsy in Sweden during 2003.METHODS: 292 patients were randomly selected from two tertiary centres (University hospital in Lund and Umeå) and complete data was obtained from 175 patients. Patients completed a 3 months prospective seizure diary, one retrospective and one prospective health care resource utilization questionnaire (3 months each). HRQL data were collected using EQ-5D and a disease-specific instrument, QOLIE-31. In addition, data was collected by physicians/nurses by a one-year retrospective patient chart review. Patients were categorized by most common seizure (sz) type(simple partial, complex partial, secondary generalized) and sz frequency (sz free, <1sz per month, >1sz per month). Direct and indirect costs were estimated using prevalence and bottom-up approach. Direct costs included inpatient care, outpatient care, pharmaceuticals and social services. Indirect costs were calculated based on the human capital theory as loss of production due to temporary sick leave and early retirement. RESULTS: The mean total annual cost per patient due to partial epilepsy was approximately 100.000 SEK, indirect costs accounting for approximately 60%. Disease specific costs varied between 50.000-170.000 SEK depending on sz type and frequency. The mean total annual cost per patient based on all data collected for the patient population was 250.000 SEK, indirect costs accounting for approximately 50%. The patient population cost varied between 100.000-420.000 SEK depending on seizure type and frequency. Patients with complex partial seizure carried the highest cost and had the lowest HRQL. Patients with no or occasional seizures reported higher HRQL than patients with more than one sz per month. CONCLUSIONS: Partial epilepsy is a serious and expensive disease. The socio-economic cost increases and HRQL deteriorates with high seizure frequency increasing frequency of seizures and with frequent complex partial seizures.