Objective: to investigate the features of the course and long-term outcome of catastrophic epilepsies. Patients and methods. A total of 130 patients (62 (47.7%) men and 68 (52.3%) women) aged 21 to 78 years were examined. The follow-up was 1 year to 14 years. The inclusion criteria for the investigation were above 18 years of age; severe epilepsy with daily seizures considered as catastrophic epilepsy. The exclusion criteria were a history of nonepileptic seizures of any etiology, as well as noncompliance. The examination included history data collection; seizure diary analysis; clinical and neurological examination; routine EEG and/or EEG-video monitoring; brain magnetic resonance imaging; and laboratory tests. Results and discussion. The onset of epilepsy immediately with catastrophic seizures was observed in 28 (21.5%) patients; this onset was most frequently seen in 18 of the 28 children. At the same time, catastrophic seizures did not appear immediately, but it took some time for them to occur after the onset of active epilepsy in 102 (78.5%) patients. Moreover, the onset of catastrophic seizures could not be associated with any external influences or errors in 58 (56.9%) of these patients taking the drugs. Transition to catastrophic epilepsy could occur both abruptly in 11 (10.8%) patients and gradually in 91 (89.2%). After treatment correction, 16.8% of patients achieved remission at the time of study completion; the frequency of seizures decreased by 50% or more in 27.1% of cases; the effect was absent in 56.1%. Conclusion. Based on the findings, it can be concluded that in catastrophic epilepsy, the probability exists for spontaneous occurrence and remission of destructive seizures, frequently regardless of the therapy. The onset of the disease and that of catastrophic seizures can be spread in time. The efficiency of treatment remains low in patients with catastrophic epilepsies.