We report autopsy cases of two brothers with the late infantile form of neuronal ceroid lipofuscinosis (LINCL) and examine apoptotic cell death in autopsied brains. Both patients showed psychomotor developmental delay, cerebellar ataxia, convulsions, visual disturbance and myoclonus, and they became bedridden around the age of 6-7 years. Macular changes, mimicking cherry-red spots, were observed on funduscopy, but conjunctival biopsy failed to disclose storage materials. In these cases, the autopsies demonstrated severe atrophy with neuronal loss and gliosis throughout the brain and spinal cord, except the hypothalamic neurons and motor neurons in the brain-stem and spinal cord, and autofluorescent lipofuscin-like materials of two types, fine granular deposits and coarse round bodies, were stored in the remaining neurons and glial cells, and in the epithelial cells of various visceral organs. Immunostaining for mitochondrial subunit C visualized the fine granular deposits but not the coarse round bodies. The nuclei of neurons and glia cells were stained by in situ nick end labeling, which was more pronounced in the younger case, although the expression of both bcl-2 and bcl-x was not significantly altered in these cases. It is suggested that immunohistochemistry for subunit C may be useful for diagnosis of NCL, and further investigations are necessary to clarify the relationship between LINCL and apoptosis, especially in severely affected cases.