In this study the direct actual costs associated with epilepsy-related health care, treatment with the novel antiepileptic drug vigabatrin (gamma-vinyl GABA, GVG), epilepsy surgery evaluation (ESE) and epilepsy surgery were analysed in 52 patients with intractable partial epilepsy who were on a waiting-list for ESE while trying GVG. Sixty percent of the 52 patients obtained a reduction in seizure frequency of 50% or more with GVG. Of the twenty-one operated patients 57% became seizure free, 10% had more than 75%, 5% had 50-75% and 29% had less than 50% reduction of seizure frequency. Of the 17 patients who did not go through ESE (the "GVG responders"), the corresponding outcome was 6%, 59%, 29% and 6%. For the 14 patients who were neither operated nor GVG responders, the outcome was 0%, 0%, 36% and 64%. The mean yearly costs (expressed in 1991 prices) of epilepsy-related health care including antiepileptic drug treatment was US $1,594 the year before starting GVG therapy, and US $2959 the first year of GVG treatment including a mean yearly cost of GVG of US $1,572. The mean total cost for ESE and surgery was US $46,778 (N = 21), while the mean cost of ESE in patients evaluated but not accepted for surgery (N = 14) was US $24,054. Considering the costs for ESE and surgery in the whole patient series, the mean total cost of rendering one patient seizure free with surgery was US $110,000. Surgery is the most effective treatment option in selected cases of severe partial epilepsy. If its costs are distributed over the patient's expected lifetime, the yearly cost is comparable to the present yearly cost of medication with GVG. However, since many patients achieve satisfactory seizure control with GVG, and considering the risks of surgery, we consider it a rational policy to let patients try this drug (or another of the new generation of antiepileptic drugs) before entering ESE.