The classification of seizures and epileptics syndromes made it possible on the prognostic level to differentiate the benign epilepsies and the serious epilepsies. In children, several concepts are to be considered for a better comprehension of the specificity of the epilepsies related to this age of the life: synaptogenesis, receptors ontogenesis and ionic channels, myelinogenesis, epigenesis. Epilepsy is often associated with cognitive disorders and behaviour disorders in children. The relations between cognitive functions and epilepsy are multifactorial with intrication of neurodevelopmental, environmental and psychogenic factors. Identification of epileptic syndromes genetically determined and genetic diseases becoming complicated by epilepsy, allow a complementary approach in the comprehension and diagnosis of childhood epilepsy.