The aim of this study is a clinical and electroencelographic analysis of those SSPE patients who suffered epileptic seizures in course of the disease. The material is based on an analysis of a computed database including 1180 case histories from multiple hospitalizations of 248 SSPE patients (141 males, 107 females) in years 1978-1995. The analysis was made using computer system EPI-INFO 6. The average age of SSPE onset was 12.3 +/- 4.5 (range 4-27.5). 74.2% of patients developed the disease before the age of 15. Epileptic seizures occurred in 43.5% (N = 108) of all SSPE patients in different stages of the disease. In 47 patients (M-21; F-26) they were observed among first SSPE symptoms, in 41 of those the seizures had the form of GTCS. Epileptic seizures were more frequent in patients with SSPE onset before the age of 15 (50.5%) than in patients with later onset (23.4%). More frequent occurrence of epileptic seizures and epileptiform changes in EEG in children under 15 can be associated with specificity of developmental age: immaturity of nervous and endocrine system and decreased convulsant threshold.