Subacute necrotizing encephalomyelopathy (SNE), or Leigh's disease, is an unusual neurologic disorder that is associated with nystagmus, strabismus, and optic atrophy in the majority of cases, and is most often described in infants. The defect currently thought to account for SNE is the presence of an inhibitor factor in the thiamine pathway. We saw a patient whose eye findings initially were believed to represent spasmus nutans, but whose clinical course, computed tomographic findings, and autopsy findings were typical of SNE.