Seventeen patients with idiopathic West syndrome and normal CTscan underwent a SPECT investigation. It is possible to perform this investigation in infants and children; the technical and methodological aspects are analysed. In benign infantile epileptic spasms, it showed no significant abnormality. In all the other cases, areas of hypovascularisation were observed. They predominated in the parieto-temporo-occipital areas both in the acute phase and several months or years later, and they correlated with the topography of predominating EEG abnormalities.