One of the most challenging areas in nosology is in the field of severe generalized epilepsy of early childhood. This is certainly true in the case of Lennox-Gastaut syndrome (LGS), an age-related epileptogenic encephalopathy which comprises several types of generalized seizures including tonic seizures, atypical absence seizures and frequent status epilepticus. EEG shows generalized slow spike waves, and as the disease progresses, cognitive functions deteriorate. LGS is listed in the 1989 classification of the International League Against Epilepsy alongside epilepsy with myoclonic astatic seizures and West's syndrome. A number of variants or atypical forms have been proposed. As a result, differential diagnosis presents a major challenge and includes specific generalized epilepsies, i.e., metabolic or inflammatory; secondarily generalized epilepsies, i.e., those arising from the frontal lobe; and severe forms of idiopathic generalized epilepsy, i.e., Doose syndrome. Antiepileptic drug (AED) treatment of LGS has been disappointing. Results obtained from anterior callosotomy have been promising, but only a small number of patients have been evaluated. Although the syndrome is rare, the severe nature and intractability of LGS emphasizes the need for the development of specific AEDs which would completely modify the quality of life for these patients.