•In cases of severe consciousness disorder with head injury, it is difficult to diagnose consciousness disorder due to VAI from cervical spine trauma because of insufficient physical and neurological findings.•We reported the case of a patient with extensive brain infarctions because of bilateral VAI without any remarkable CT findings suggestive of VAI.•When cervical hyperextension injury is suspected, CTA should be performed as early as possible to initiate early treatment of extensive brain infarction due to bilateral VAI. Vertebral artery injury (VAI) is not uncommon following blunt neck trauma, although bilateral VAI—which is rarer—can be fatal. We present the case of a 77-year-old man who was transported with a head injury and consciousness disorder. No hemorrhagic lesions in the patient’s head were noted using computed tomography (CT). Mild anterior opening between the fourth and fifth cervical vertebrae (C4 and C5) and multiple spinous process fractures between C4 and the first thoracic vertebrae (T1) were detected. No CT findings suggestive of VAI were noted. Brain magnetic resonance imaging (MRI) findings showed extensive brain infarctions, bilateral VAI, anterior longitudinal ligament injury, disc injury at C4/5, and retropharyngeal hematoma. He was admitted to the intensive care unit, but his family refused invasive surgical treatment; he died 6 days after admission. The extensive brain infarctions were considered to be associated with bilateral VAI because of cervical hyperextension injury. This case highlighted the importance of considering brain ischemia due to VAI, as a differential diagnosis, in patients with consciousness disorder and possible cervical hyperextension injuries, even in the absence of CT findings suggestive of VAI. In such patients, CT angiography should be performed early to evaluate the possibility of VAI.