Five cases of syphilitic aortic aneurysm with erosion of the spinal column are reviewed. Four patients underwent operation. When erosion of the spine was mild or moderate, the aortic lesion only was treated. Aneurysm associated with extensive vertebral erosion was treated in two cases by anterior spinal fusion combined with replacement of the disc and part of the aorta. In one of these cases the spine was later reinforced by a posterior spinal fusion. One patient so treated died a week after operation. The patient who refused operation later developed a complete paraplegia.