This report describes a male patient who presented with symptoms suggestive of spinocerebellar degeneration and who died of respiratory failure at the age of 7 years but was diagnosed, at autopsy, as having neuronal intranuclear hyaline inclusion disease. Neuronal intranuclear hyaline inclusion disease is a progressive and degenerative disease; diagnosis is possible only by neuropathological analysis. This is a rare disorder; few cases with early childhood onset and rapidly progressive neurologic symptoms have been documented. According to previous reports, most neurons in the central nervous system exhibited intranuclear eosinophilic inclusion bodies; neuronal depletion appeared to be restricted to the cerebellar cortex and the medullary inferior olivary nuclei, consistent with the fact that clinical deficit appears to correspond to the site of neuronal depletion and not to where eosinophilic bodies are detected. Immunohistochemical analysis revealed that these inclusions were positive for ubiquitin. The case presented herein clearly indicates that neuronal intranuclear hyaline inclusion disease should be considered as a differential diagnosis of cases involving spinocerebellar degeneration with childhood onset.