Cortical necrosis is an uncommon cause of renal impairment and is rarely a consequence of blunt abdominal trauma. We present a case of unilateral traumatic acute cortical necrosis in a child demonstrated on contrast-enhanced US with confirmation on MRI. Contrast-enhanced US provides a rapid, accurate evaluation of renal parenchyma abnormalities in blunt abdominal trauma in children without exposure to ionising radiation or the risk of sedation.