With limited near-field resolution and accessible acoustic windows, sonography has not been advocated for assessing central nervous system injuries in the shaken-baby syndrome. Our purpose was to correlate high-resolution ultrasonographic characteristics of central nervous system injuries in whiplash injuries and the shaken-baby-syndrome with MRI and CT. Ultrasonographic images of 13 infants, aged 2-12 months, with whiplash or shaking cranial trauma were reviewed and compared with MRI in 10 and CT in 10. Five patients had serial ultrasonography and MRI or CT follow-up from 1 to 4 months after the initial injury. With ultrasonography we identified 20 subdural haematomas. MRI and CT in 15 of these showed that four were hyperechoic in the acute stage, three were mildly echogenic in the subacute stage, and that one subacute and seven chronic lesions were echo-free. Five patients had acute focal or diffuse echogenic cortical oedema which evolved into subacute subcortical hyperechoic haemorrhage in four, and well-defined chronic sonolucent cystic or noncystic encephalomalacia was seen at follow-up in two. Using ultrasonography we were unable to detect two posterior cranial fossa subdural haematomas or subarachnoid haemorrhage in the basal cisterns in three cases, but did show blood in the interhemispheric cistern and convexity sulci in two. U1-trasonography has limitations in demonstrating abnormalities remote from the high cerebral convexities but may be a useful adjunct to CT and MRI in monitoring the progression of central nervous system injuries in infants receiving intensive care.