Twenty-five children with post-hemiconvulsive hemiplegia, who had had epileptiform discharges on EEG, were followed for over 5 years. Twenty-two of them developed the hemiconvulsion-hemiplegia-epilepsy syndrome. The computed tomographic (CT) findings were: marked hemispheric atrophy in 13 cases; moderate or slight hemispheric atrophy in 4; focal atrophy or porencephaly in 4, and a normal scan in 4. The electroencephalographic (EEG) findings showed residual asymmetry of hemispheric amplitudes in 15 cases. Epileptiform discharges on EEG were found on the ipsilateral side (the damaged hemisphere) in 13 cases, the contralateral side (the undamaged hemisphere) in 9, and on both sides in 3. As to the correlation between CT and EEG abnormalities, 8 of 13 cases with marked hemiatrophy on CT had contralateral epileptiform discharges on EEG, and the converse was more pronounced: 8 of 9 cases with contralateral epileptiform discharges had marked hemiatrophy on CT. Contralateral epileptiform EEG abnormalities were observed in the patients with severe hemispheric brain damage.