Cranial ultrasonography was used in the initial evaluation of 40 infants with macrocrania. Three of the infants had normal findings. The other 37 had evidence of various types of abnormality: intraventricular obstructive hydrocephalus, external hydrocephalus, arrested hydrocephalus with atrophy, or mild ventriculomegaly. All the infants were given neurological and developmental examinations at the time of presentation and were followed up for one year. Sonograms and head-circumference and intracranial pressure measurements were done at intervals, according to the initial ultrasound findings and the clinical status of the children. Neurodevelopmental outcome was related to the type of abnormality. The majority of children with external hydrocephalus were neurodevelopmentally normal at follow-up. In contrast, those with obstructive or arrested hydrocephalus had unfavourable outcomes, which may be related to the significant perinatal insult causing the hydrocephalus. CT confirmation was available for 16 of the infants.