Little information exists concerning voiding dysfunction associated with diastematomyelia (splitting of the spinal cord). We present 27 patients 4 days to 62 years old (mean 13 years) who underwent neurosurgical intervention for treatment of this disorder. Of these patients 14 had urological evaluation, with 11 having undergone video urodynamics. Nine patients had minimal urological manifestations. No patient had a urodynamically proved hostile bladder nor evidence of upper urinary tract deterioration. In our experience, patients with a spinal cord fixation syndrome resulting from diastematomyelia not associated with a meningomyelocele appear to have a relatively benign course in terms of the urological manifestations. However, due to the lack of reports concerning the urological findings in this occult dysraphic state, we still suggest upper and lower urinary tract evaluation and followup.