We report a 46-year-old female who presented progressive ophthalmoplegia and limb weakness. She was well until the age of 15 years when there was an onset of bilateral deafness. She became completely deaf by 20 years of age. She noted an onset of weakness in her legs when she was 27-years-old and of ptosis at 34 years of age. She was admitted to our hospital when she was 41-years-old. Neurological examination revealed near total ophthalmoplegia, bilateral ptosis, dysphagia, generalized muscle atrophy and weakness of approximately 4/5 degree, facial grimacing, athetotic movements in four limbs. Laboratory examinations revealed increase in blood lactate and pyruvate levels and diffuse low density change in the cerebral white matter in CT scans. She was thought to have a mitochondrial encephalomyopathy. She was discharged for follow-up, but her clinical course was that of a relentless deterioration. She was readmitted to our service in December 1989. She showed further progress in her weakness and muscle atrophy. Otherwise neurological examination was essentially similar to the previous one. Her cranial CT scans showed low density changes in striatum, thalamus and midbrain in addition to the white matter. Enzyme activities of the electron transport complexes revealed a moderate decrease in the succinatecytochrome c reductase activity, and the Southern blot analysis of mtDNA revealed multiple deletions in mitochondrial genomes. Two months after her admission, she developed bronchopneumonia, and expired on March 13th, 1990. Post-mortem examination revealed diffuse pallor of myeline in the cerebral white matter in K-B staining. A marked neuronal loss and gliosis were observed in putamen bilaterally. Skeletal muscles showed typical changes of mitochondrial myopathies with ragged-red fibers in Gomori-Trichrome staining, and crystalline inclusion bodies by electron microscopic observations. Some neurogenic atrophies were also seen. Oculomotor nuclei appeared intact. It was thought that she had an incomplete form of Kearns-Sayre syndrome. The patient was discussed in a neurological CPC of the departments of Neurology and Pathology of Juntendo University School of Medicine.