In the fetal lamb model of hypoxic-ischaemic injury, the insult is followed by EEG depression, after which seizures emerge at 7-13 hours. We explored the relationship between the emergence of electrographic seizures and our estimate of the time of the cerebral injury in nine babies who underwent continuous video-EEG monitoring from soon after birth. Babies with prelabour insults had their first seizures before 12 hours of age, whereas those whose insult was peripartum had seizure onset at 18-20 hours of age. EEG seizure onset time could have important clinical and medico-legal applications, and be related to the time or severity of the insult, or both.