An intra-abdominal mass was observed by fetal ultrasonography at 32 weeks of gestation. The baby was diagnosed as having neuroblastoma at the time of delivery at 39 weeks and its lower extremities were completely paralyzed. The chemotherapy after birth was quite effective to reduce the mass volume but neurological sequelae failed to improve. By carefully monitoring the movement of extremities, it may have been possible to prevent irreversible paralysis by inducing delivery before that state was reached.