This paper analyzes the results of a survey of 785 patients referred to our hospital with a diagnosis of epilepsy. Diagnosis of forms of epilepsy and definition of the localization of epileptogenic focus in patients with focal epilepsy (FE) were performed using the method of video-EEG monitoring. Every fifth patient with suspected ongoing seizures has nonepileptic paroxysms. FE was found in 92,6% of patients in a children's epileptological hospital and about half of them (48,2%) had a frontal localization. The presence of «generalized» types of seizures and «generalized» epileptiform activity on EEG was the feature of FE at the early age. The discordance of interictal focus and onset zones was observed in 22,8% of cases; 9,4% of patients with FE had more than one cortical area responsible for the generation of epileptic seizures. The localization of the epileptogenic zone can not be reliably established without an analysis of ictal EEG. All these cases are related to the early childhood (0-3 years), which indicates the need for recording multiple seizures (> 5) to identify the epileptogenic zone in this age group. Accuracy and reliability of diagnosis have special value in case of preparation of the patient with FE to surgical treatment.