Surgery for intractable epilepsy is a widely used treatment that is not readily assessed by randomised trials. We evaluated the impact of epilepsy surgery on seizures, medication use, employment, and the quality of life in 248 adults and adolescents consecutively referred to one medical centre between 1974 and 1990. Outcomes were determined through self-administered questionnaire and medical record review for 202 surgery and 46 non-surgery patients whose treatment was usually determined by the presence or absence of an epileptogenic focus. Surgery and non-surgery patients differed at baseline only in median monthly seizure frequency (surgery lower than non-surgery). After adjustment for baseline covariates, surgery patients at follow-up had greater decline in average monthly seizure frequency (-11.9 vs - 1.5; difference -10.4, 95% CI -20.5, -0.3) and took fewer antiepileptic medications (average number 1.4 vs 2.0; difference -0.67, 95% CI -0.94, -0.40). Although quality-of-life scores were higher (p < 0.05) with surgery on 5 of 11 scales that were administered only at follow-up, there were no significant differences in employment status or prospectively assessed quality of life. Relative to a non-surgery group, patients treated surgically had better seizure control with less antiepileptic medication. The impact of epilepsy surgery on quality of life and employment needs to be assessed in larger prospective studies.