Immediate postoperative paresis following spinal fusion for scoliosis is uncommon. This neurological disaster can occur either within hours or days after surgical correction of the curvature. Paresis of the right lower extremity occurred on the third postoperative day in a 15-year-old boy who underwent spinal fusion for a pseudarthrosis of a previous fusion and in whom a Harrington rod was inserted for stability but not correction. The rod was removed within four hours of recognition of the paresis; within 18 months the child made an almost complete recovery of all motor function; slight residual weakness of the anterior dorsiflexors of the foot still remain.