A study included 113 patients with localization-related epilepsy treated with antiepileptic drugs: 53 patients with drug-resistant (uncontrolled) form of the disease and 60 patients with controlled epileptic seizures. A comparison group included 53 patients with rare seizures not taking antiepileptic drugs. In the group of patients with uncontrolled localization-related epilepsy, the EEG monitoring of the sleep-wake cycle revealed more frequent regional interictal epileptiform discharges and increased α- and β-activities during sleep compared to wakefulness. In patients with controlled seizures, there were the circadian changes in intra- and inter-hemispheric coherent relations in θ- и β-bands. These relations remained stable when the sleep phase was changed to the wake phase.