A heterogeneous series of 79 children with partial epilepsy was studied by computerized tomography (CT) and magnetic resonance imaging (MRI) to evaluate the contribution of MRI to the aetiological diagnosis of that disease. Both CT and MRI were normal in 13 cases and abnormal in 41 cases showing the same pathology (malformation, atrophy, tumour, scar). In 4 cases of continuous partial epilepsy the lesions observed were either diffuse or focal corresponding to the electrical focus, and they could be due to Rasmussen's encephalitis. In 19 cases where CT gave normal results, MRI showed bilateral high-intensity signal areas of uncertain significance in the white matter of the caudal part of the hemispheres. All considered, it seems that with its greater sensitivity MRI should be the first or only exploratory method to be used in the evaluation of partial epilepsy of childhood.