Clinical seizures, or subclinical EEG discharges, were observed in sixteen new-born babies or infants under one year of age admitted to hospital. Clinical observation and initial biological tests showed that: --seizures occurring during rehydration of infants with salt retention are not associated with severe neurological lesions,--in dehydrated babies, a dissociation between electroencephalographic and clinical manifestations (electrical discharges without clinical signs or vice versa) and large abnormalities in the intercritical tracing are bad prognostic elements;--in new-born babies with severe dehydration and meningeal hemorrhage, the occurence of clinical and electroencephalographic seizures does not imply that there will be an unfavourable evolution. The authors discuss the physiopathological correlations arising from the study of this series.