Megimide-induced epileptic seizures were recorded in nine male El and six male ddY mice with the chronic implantation technique for monopolar recording of electrocorticogram (ECoG). ECoG were recorded from preictal period until 30 min after general tonic clonic convulsion (GTC). In total, 14 GTC in ddY and 15 in El were recorded. There were three periods as for clinico-ECoG correlate in both strains: a twitching period, GTC, and a postictal period. The GTC had three phases: a tonic phase, a tonic phase with clonic movements, and a clonic phase. Twitching movements (twitching period) consisted of rapid backward jerks of the neck, associated with different electrocortical phenotypes: focal spikes, generalized spikes, or generalized spike and wave complex. During tonic phase of GTC, clonic movement of the limbs was the most frequently observed clinical phenotype, whereas twitchings were the predominant manifestation during clonic phase of GTC in both strains. The ictal ECoG phenotype was strain specific: generalized spikes predominated in ddY and occipital spikes in El mice. There were postictal spikes without specificity for localization in both strains.