BACKGROUND Brown-Sequard syndrome (BSS) has been reported in patients with various spinal pathologies, including spinal traumatic injuries, spinal cord neoplasms, epidural hematomas and spinal cord ischemia. Pure BSS caused by cervical disc herniation is very rare. METHODS We report a rare case of cervical disc herniation presenting as BSS associated with Horner syndrome (HS), which has not been reported up to now. A prompt diagnosis by magnetic resonance imaging (MRI), followed by spinal cord decompression was performed. A postoperative rapid improvement of the neurological deficits was observed. CONCLUSIONS We review the literature and discuss the functional anatomy of spinal cord of BSS combined with HS. And it is important that clinicians be aware that a MRI of spinal cord is needed for those patients with a thoracic sensory level, and that a thoracic sensory level might not only depend on the level of spinal cord injury but also on the stage of evolution of the lesion.