In the few previously autopsied patients with the Kearns-Sayre form of progressive ophthalmoplegia, the most prominent abnormalities have been in muscle, with less conspicuous changes in the central nervous system, primarily in the brainstem. Similar findings were present in the case reported here, but in addition there was severe demyelination in the initial few millimeters of the cranial and spinal motor roots distal to the glial-Schwann cell junction. Milder demyelination was observed in the dorsal spinal and afferent cranial nerve roots, including the eighth nerve, but deafness was due to virtually total destruction of the organ of Corti. Our observations suggest that a radiculopathy may be a feature in some cases of Kearns-Sayre syndrome.