Our knowledge in the field of epilepsy has evolved since the discovery of new specific inherited epilepsy syndromes. Causal mutations have been identified for some of these syndromes. They involve various ionic channels: Na⁺ channels in the generalized epilepsy with febrile seizures plus (GEFS+) among the idiopathic generalized epilepsies, nicotinic receptors in autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), K⁺ channels in benign familial neonatal convulsions, and GABA_A receptors in some forms of generalized epilepsy. The major challenge that lies ahead is to solve the genetics of the common forms of epilepsy following complex inheritance. It is likely that a number of genes coding for one or more ion channels may interact to produce specific epilepsy syndromes. A number of classical idiopathic generalized epilepsies have been mapped but no genes identified to date. It remains to be seen whether the molecular insights gained from the monogenic epilepsies will be directly relevant to the common epilepsies.