Congenital bilateral perisylvian syndrome (CBPS) is a rare neurological disorder characterised by pseudobulbar palsy, cognitive deficits and epilepsy associated with bilateral perisylvian cortical dysplasia on neuroimaging studies. We report a long-term follow-up of a 18-years girl diagnosed with CBPS according to the typical clinical and magnetic resonance imaging (MRI) features. The patient showed faciopharyngoglossomasticatory diplegia, severe dysarthria, ataxia, spastic quadriparesis and severe mental retardation. Brain MRI evidenced bilateral perisylvian cortical dysplasia. Since early life she suffered from complex febrile seizures and epilepsy consisting of complex partial attacks with affective manifestations associated with centro-temporal EEG abnormalities. During 18 years of follow-up she was treated with phenobarbital, carbamazepine, lamotrigine, gabapentin but did not show any significant clinical improvement. Subsequently, monotherapy with phenytoin (PHT) was followed by a significant clinical improvement. At age 17, because of adverse effects, PHT was gradually substituted by topiramate (TPM). Full control of seizures was obtained at the age of 17 years with TPM. EEG abnormalities throughout the years have been reduced according to the clinical course. These findings emphasised the importance of long-term follow-up, suggesting that the prognosis for epilepsy may not be predicted based on the early response to treatment or on the presence of structural encephalic abnormalities, as reported in the literature.