The outcome of 151 children less than 15 years of age and admitted within 24 h of head injury was studied in relation to clinical and computed tomography (CT) scan features. Thirty one (20.5%) had a poor outcome (24 died, 6 were severely disabled at 6 months after injury and 1 was in a persistent vegetative state) while 120 (79.5%) had a good outcome (89 recovered well and 31 were moderately disabled). Factors associated with a poor outcome were Glasgow Coma Scale (GCS) score 24 h following injury, presence of hypoxia on admission and CT scan features of subarachnoid haemorrhage, diffuse axonal injury and brain swelling. GCS scores alone, in the absence of other factors, had limited predictive value. The prognostic value of GCS scores < 8 was enhanced two-to fourfold by the presence of hypoxia. The additional presence of the CT scan features mentioned above markedly increased the probability of a poor outcome to > 0.8, modified only by the presence of GCS scores > 12. Correct predictions were made in 90.1% of patients, indicating that it is possible to estimate the severity of a patient's injury based on a small subset of clinical and radiological criteria that are readily available.