A linear-array real-time ultrasound scanner with a 5 MHz probe was used to examine the brains of 31 infants born at less than 33 weeks of gestation. The equipment was mounted on a small trolley and the infants could easily be scanned in their incubators. 7 of the 31 infants were shown to have cerebral lesions, including haemorrhages into the germinal layer and ventricles, hydrocephalus, and infarction of the periventricular region and cerebral cortex. The type and extent of the lesions were conformed by computerised tomography and at necropsy. Ultrasound scanning is a safe, simple, non-invasive technique that provides valuable information for the diagnosis, investigation, and treatment of lesions in the brains of newborn infants.