The paper summarizes the main results of analysis of electroencephalograms in rats with genetic predisposition to absence epilepsy (WAG/Rij rat strain). Properties of epileptic activity are described in time and in frequency domains; dynamics of epileptic activity is investigated, as well as changes in electroencephalogram structure prior to epileptic discharges. Physiologic interpretation of the investigated phenomena helps in better understanding of the nature of the investigated phenomena.