PURPOSE: To investigate health-related quality of life (HRQOL) in relation to seizure outcome as part of a multicenter follow-up of epilepsy surgery in Sweden. METHODS: A battery including the SF-36 Health Survey and the Hospital Anxiety and Depression scale (HAD) was distributed to all patients older than 16 years. Mean follow-up time was 4 years (range, 2-13 years) and response rate, 91% (103 of 113 patients). HRQOL data were related to seizure frequency and severity (Chalfont Seizure Severity Scale). RESULTS: Seventy-six percent considered their global health to be better than it was before surgery. Degree of improvement in seizure control correlated with improved satisfaction with health (Spearman's r = 0.44). Higher SF-36 scores (higher HRQOL ratings) correlated with percentage reduction of seizure frequency for all scales and was strongest for perception of general health (Spearman's r = 0.46). When the patients were divided into four categories [A, completely seizure free (n = 29); B, seizure free with aura (n = 18); C, > or =75% reduction in seizure frequency (n = 24); and D, or =75% reduction in seizure frequency, low seizure severity correlated with higher HRQOL ratings for scales measuring social function, vitality, and mental health. Depression levels (HAD scale scores) were on average low. Anxiety (HAD) increased significantly from A to D. CONCLUSIONS: HRQOL seems to be scored as a continuum in relation to seizure frequency. Seizure severity measures give complementary information.