Objective. To identify neurophysiological markers of focal and generalized epileptic seizures in the inter-epileptic period. Material and methods. Sixty-four patients, including 36 with isolated generalized tonic-clonic seizures and 28 with focal seizures, were examined. The control group consisted of 27 healthy people. EEG-video monitoring and bioelectric activity analysis of the brain during wakefulness and day sleep, spectral EEG analysis, quantitative and quality indicators of sleep were used. Results and conclusion. In generalized epileptic seizures, alpha rhythm is predominantly recorded in the left hemisphere. In wakefulness, the focal epileptiform activity develops during the first two stages of day sleep. In focal epileptic seizures, delta and beta-2 rhythms were recorded in the left hemisphere, regional epileptiform changes are aggravated during the 1st and 2nd stages of slow sleep initiated in the frontal regions. A focal component of the epileptiform activity in the inter-epileptic period in patients with different types of seizures should be taken into account in examination and treatment planning of patients who had difficulties with the diagnosis of epilepsy type.