Head injuries are a significant cause of morbidity and mortality in children. A descriptive multiple-case study was used to compare the accuracy of two assessment scales in children aged under 5 years. The study emphasised the importance of prompt and accurate assessment of children with head injuries. The Glasgow Coma Scale (GCS) is inappropriate for use in young children. The Adelaide Coma Scale (ACS) is a more appropriate tool for those aged under 5 years because it takes the child's age, and, therefore, neurological immaturity, into account. However, the ACS still does not give enough scope for assessment. If the ACS is used, therefore, additional information must be considered, including specific paediatric indicators, and an assessment of each child's behaviour according to the main care giver.