Patients with partial seizures aged 1 week to 19 years (n = 175) were included in several prospective vigabatrin studies at the hospital Saint Vincent de Paul. A decrease in seizure frequency of over 50% was achieved in 70% of patients, with 30% becoming seizure free, and only 6% experiencing an increase. Tuberous sclerosis gave the best response (85%), tumors the lowest (45%), the usual figure for other causes being 70%. Patients with malformations were the most likely to experience seizure increase. Regarding topography of focus, the lowest rate of seizure-free patients was in rolandic foci. Early treatment produced better results. Infants experienced the highest rate of response, but also of relapse, the latter occurring mainly between 6 months and 1 year. The incidence of loss of efficacy depended on etiology and topography of focus, tumors and frontal foci having the highest risk. Occurrence of new seizures was more frequent in young patients with tuberous sclerosis, the third experiencing status epilepticus. Vigabatrin monotherapy could only be achieved in 33% of seizure-free patients, reduction of comedication being a risk of relapse and of further intractability.