We present a case of posttraumatic infarction in the territory supplied by the lateral lenticulostriate artery after a minor head injury in a child. A 2.5-year-old child was admited to our emergency room after a head-on fall from a height of 50cm. He developed a right hemiparesis and he could not speak properly for about half an hour. An initial computerized tomography of the head taken two hours after the accident was normal. A follow-up CT obtained two days later revealed a hypodense lesion at the left basal ganglia and a diffusion-weighted magnetic resonance imaging disclosed an area of infarction. The patient was conservatively medicated and full recovery was made in three weeks. Hospital admission, careful observation and early diffusion-weighted MR examination should be considered for patients with persistent neurological deficits.