Post-irradiation cerebral pathologies may appear in various forms from localized radiation necrosis to a plurifocal type or from local to diffuse vasculopathies. Contrary to the current prevalent opinion, these lesions are not rare in children since young nerve tissue is particularly sensitive to ionizing radiation. Given the seriousness of some of these lesions, the authors recommend careful evaluation of the risk involved in relation to the real necessity of administering irradiation therapy in childhood.