Twenty-three subjects from two family groups with the adrenoleukodystrophy (ALD)-adrenomyeloneuropathy (AMN) complex were examined with MR imaging at 1.5 T to determine the presence and extent of brain and spinal cord abnormalities. Nineteen individuals were identified as having ALD or AMN, or as having carrier status on the basis of pedigree analysis and/or evaluation of serum very-long-chain fatty acids. In addition to the expected intracranial white matter changes for this disorder, decreased spinal cord diameter was found in seven (30%) of the 23 subjects. In three of these cases, atrophy was limited to the thoracic spinal cord, while atrophy of both the cervical and thoracic cord was identified in four patients. Two patients who did not have MR imaging of the spine were found to have spinal cord atrophy at autopsy. The finding of decreased spinal cord diameter on MR examinations in individuals who are heterozygous for ALD-AMN, in patients with ALD or AMN, and in asymptomatic ALD-AMN patients may represent a new anatomic marker for the variable clinical presentations of this condition. In addition to cranial MR examination, MR imaging of the spine may be indicated in patients with suspected ALD or AMN, or in women with carrier status.