A boy aged 5 had displayed from the age of 3 a fluctuating deficit in understanding spoken language. Audiometric testing proved his hearing to be normal. After 18 months, the parents noticed minor attacks of 'absence'. An EEG showed a normal background pattern and frequent spikes and spike waves complexes; CT-scanning of the brain revealed no abnormalities. On the basis of the acquired language disorder, the seizures and the features of the nocturnal EEG, the diagnosis the syndrome of Landau-Kleffner was made. After treatment with ethosuximide a temporary improvement of the aphasia occurred. A permanent improvement however was realized by treatment with prednisone. The boy could attend a primary school. The syndrome runs a fluctuating course; the patient may recover, but he may also undergo general mental deterioration. Antiepileptic agents only may have a brief favorable effect on the aphasia. In case of failure corticosteroids or even subpial cortical transsection are indicated.