Selective cervical nerve root block is executed for patients who have symptoms of cervical radiculopathy for diagnostic and therapeutic purposes. However several catastrophic complications caused by this procedure have been reported including neurological complications. A 43-year-old male received a C5 selective cervical nerve root block procedure due to continuous radiating pain even after cervical discectomy and interbody fusion was performed. At the time of the procedure, the contrast outline revealed reflux of the nerve root and epidural space. But after the procedure was performed, the patient experienced decreased sensation in the upper and low extremities as well as motor paralysis of both extremities. Our sspecting diagnosis was anterior spinal artery syndrome but both sensory and motor functions were subsequently recovered within a few hours after the procedure was completed. Due to the difficult nature of this case, we reported these complications and reviewed current literature related to this study.