Three cases of severe spinal kyphotic deformities were treated with Halo-pelvic Apparatus. Among these three cases, two were tuberculous kyphotic deformities involving the thoracolumbar vertebrae with paraplegia. And the other one was cervical kyphotic deformity due to neurofibromatosis with neurologic involvement. The following results and considering problems were obtained. 1. Two cases of tuberculous kyphosis, 130° and 115°, were corrected to 120° and 100° respectively. And one case of neurofibromatic kyphosis, 90° was corrected to 53°. 2. Among two cases of tuberculosis in which the one was revealed full neurologic recovery, and the other resulted in permanent paraplegia. And a case of neurofibromatosis was fully recovered neurologically. 3. Total period of immobilization with Halo-pelvic Apparatus was 16, 18, 18 weeks in three cases respectively, but there was no avascular necrosis of odontoid process. 4. One case of neurofibromatosis with anterior spinal fusion revealed no loss of correction of kyphosis. But two cases of tuberculosis without anterior spinal fusion showed loss of correction of kyphosis, 20° respectively. 5. Removal of internal kyphosis was not easy, because it is likely to injury the blood supply to spinal cord. 6. During distraction, severe pain was noticed in the rib cage, which prevented further distraction. 7. After 9 weeks, ambulation with Halo-pelvic Apparatus was hindered with pain due to pelvic pin loosening. 8. In order to prevent loss of correction of kyphosis, it was considered that anterior spinal fusion should be followed by posterior spinal fusion.