A 19-year-old man presented with delayed paraplegia on the second day after a stab injury of the spine. Magnetic resonance imaging showed herniation of the spinal cord through the dural defect. After emergency surgery, his paraplegia recovered leaving a Brown-Sequard syndrome immediate after injury. Spinal cord herniation should be considered as one of the possible factors in patients developing neurological deterioration after a stab injury of the spine. The possible pathogenesis of symptomatic non-spontaneous spinal cord herniation is discussed.