To evaluate the incidence and risk factors for posttraumatic seizures (PTS).The authors conducted a prospective study of 237 patients with TBI of varying severity. The patients were hospitalized and examined in Moscow neurosurgery departments. Then they participated in the follow-up observation for 2 years. PTS were classified as early (occurred from 1 to 7 days after TBI) and late (occurred later than 7 days).Forty-three people (18.1%) experienced early seizures, 15 patients (6.3%) had late seizures. The early seizures were the significant predictor of the late seizures. In the group of patients with early seizures, the proportion of severe TBI was significantly higher. Subdural hematoma, depressed skull fracture, alcohol abuse were reliable predictors of early and late PTS. Thus, these factors increased the risk of posttraumatic epilepsy (PTE).