Hemispherotomy can be a useful procedure in hemispheric syndromes, such as Rasmussen's encephalitis, congenital stroke, or hemimegalencephaly. The seizures associated with these syndromes usually remit immediately after hemispherotomy. Presently described is a patient who had a functional hemispherotomy for a congenital middle cerebral artery stroke and whose seizures remitted 2(1/2) years after the operation. His postoperative electroencephalogram showed contralateral abnormalities. However, these disappeared with the remission of seizures. One may argue that the disconnection of the abnormal hemisphere could result in the cessation of the epileptogenic potential of the healthy hemisphere by terminating secondary epileptogenesis.