A 15-year-old teenager with Type 1 Neurofibromatosis presented with grade 4 spondylolisthesis over T12/L1 junction resulting paraparesis (Frankel D). Radiograph showed a Cobb angle of 88 degrees. Computed tomography scan showed dysplastic vertebral bodies, pedicles and facet joints of T11, T12 and L1 vertebra with complete T12/L1 facets dislocation. Magnetic resonance imaging confirmed presence of spinal cord compression. He underwent posterior instrumentation and posterolateral fusion (T8 to L4) using hybrid instrumentation. Extensive corticotomy of the posterior elements was followed by the use of large amount of bone graft. Post operatively, his neurology improved markedly back to normal. Radiographs showed a good correction of the deformity. He was immobilized in a thoracolumbar orthosis for six months. A solid posterior fusion was achieved at six months follow up. At 36-month follow up, he remained asymptomatic. This case report illustrates a successful treatment of a grade 4 thoracolumbar spondylolisthesis secondary to neurofibromatosis with posterior spinal fusion alone.