Magnetic resonance (MR) imaging and CT were used in supporting the diagnosis of Leigh disease (subacute necrotizing encephalomyelopathy) in five patients. Two cases were confirmed at postmortem examination, and three patients have laboratory and/or clinical histories suggestive of Leigh disease. Four cases demonstrated findings in the basal ganglia, especially the putamina, with symmetrical areas of low attenuation on CT. Correspondingly, on proton saturation and T2-weighted pulse sequences, these areas showed high intensity signal characteristics by MR. Similar findings were noted in the caudate nucleus (two cases). Magnetic resonance proved to be superior to CT in establishing other areas of involvement: tectum and tegmentum (one case) and medullary olive (one case). Pathology identified these lesions as representing necrosis. Magnetic resonance may be diagnostic in the appropriate clinical setting.