Archival material and clinical data of 10 autopsy cases of Leigh's disease (LS), aged from 44 days to 9 years at death, were reviewed. Development delay, irregular respiration, feeding difficulty, and abnormal eye signs were the most common symptoms. Seizures (five of ten cases) were also frequent. In most patients, the diagnosis of LS was established postmortemly by the presence of symmetrical spongiform lesions affecting several brain centers at autopsy. The histologic examination disclosed associated hypertrophic cardiomyopathy in six cases, while fatty infiltration of the hepatocytes was observed in four cases. Microvesicular degeneration of the renal tubular epithelial cells was also seen in four cases. Our observations suggest that liver and kidney involvement is a component of LS and that this rare entity has to be considered as a polysystematic disorder, able to affect other organs besides the nervous system and the heart, a fact which has not been emphasized enough in the existing literature.