Objective — the objective of the study was to determine significant differences in electrocorticographic patterns for various types of focal cortical dysplasias. Material and methods. 42 patients diagnosed with drug-resistant focal epilepsy were operated on at the Burdenko Neurosurgical Institute in the period from 2006 to 2013. Patients who were histologically diagnosed with focal cortical dysplasia (FCD) and underwent video-electroencephalography and electrocorticography were analyzed. Results. The classification of epileptiform patterns proposed by Palmini in 1995 was used. The sporadic epileptiform activity pattern was predominant in electrocorticographic studies. The continued pattern was more frequent in the case of type II focal cortical dysplasias (FCDs), both combined and isolated; burst and sporadic activity patterns prevailed in combinations in the case of type III FCDs. A uniform distribution of all pattern types of the epileptiform activity was observed in type I FCDs. The data are statistically significant for groups with sporadic and continued patterns. Conclusion. The continued epileptiform activity pattern is predominant in type II focal cortical dysplasia that corresponds to the most pronounced epileptogenesis processes of brain tissue with the presence of pathological forms of neurons. A uniform pattern distribution is observed for type I FCD. Patterns of the epileptiform activity and sporadic spike bursts are predominant in the case of type III FCDs. The sporadic activity is likely to be non-specific and almost uniformly distributed in all types of cortical dysplasias.