The study is a community-based study carried out in the UK to determine the characteristics of patients receiving treatment for epilepsy, with particular reference to the duration, nature and severity of epilepsy. 119 participating general practitioners distributed questionnaires to 2528 patients taking medication for epilepsy. Information requested included the age and sex distribution of the patients, seizure type, duration of epilepsy and frequency of seizures, employment status of the patients, and state benefits received. 1628 patients replied. The prevalence of people receiving treatment for epilepsy was estimated at 4.5/1000. Fourteen per cent were under the age of 20 years and 23% were aged 60 or more. Seventy per cent had had epilepsy for at least 5 years, while 8% had been diagnosed in the previous year. Fifty-three per cent had had one or more seizures in the year prior to the survey, and 20% had seizures at least monthly on average. Most patients had seizures of partial origin. The rate of unemployment and receipt of social security benefits was higher than in the general population. The study indicates that the majority of patients receiving treatment for epilepsy in the community have long-standing epilepsy, often intractable to medical treatment, and associated with considerable social handicap. Health care planning should take this into account.