We reviewed the results for forty-three patients who had a diastematomyelia. All of the patients had been skeletally immature when the diagnosis was made, the mean age being six years (range, birth to thirteen years), and were skeletally mature by the time that they were evaluated by us. When they were first seen at our institution, twenty-four patients (56 per cent) had a cutaneous lesion, such as hairy patch, dimple, hemangioma, subcutaneous mass, or teratoma at or near the level of the diastematomyelia; thirty-four patients (79 per cent) had congenital scoliosis; and forty-two patients (98 per cent) had at least one associated musculoskeletal anomaly, such as spinal dysraphism, asymmetry of the lower extremities, club foot, or a cavus foot. In twenty-seven patients (63 per cent), the diastematomyelia was located in the lumbar spine. Thirty-six patients had eighty-four neurological manifestations. Resection of the spur was performed in thirty-three patients at a mean age of seven years (range, three months to seventeen years). Twenty-two patients who had a resection had no change in neurological condition, nine patients had improvement, and one patient had one symptom improve and another symptom worsen after the operation. We believe that resection of the spur should be performed in patients who have progressive neurological manifestations. Patients who do not have progressive neurological manifestations should be observed; if progression is noted, a resection should then be performed.