The purpose of this study was to correlate postmortem magnetic resonance imaging (MRI) with histopathologic findings in brains of a series of autopsied patients with infantile neuronal ceroid-lipofuscinosis, a recessively inherited progressive encephalopathy. Eight formalin-fixed brains (age range at death, 7 to 13 years) were examined with MRI. One patient had also undergone brain MRI 2 years before death. Histopathologic analyses were made from standard areas selected on the basis of the MRI scans. Postmortem MRI findings did not differ significantly from the findings in the patient who was also examined during life. Typical findings were extreme cerebral atrophy and hypointensity of the gray-matter structures in relation to the white matter on T2-weighted images, a pattern the reverse of normal. Characteristic histologic findings were almost complete loss of cortical neurons and secondary loss of axons and myelin sheaths in the white matter. The drastically altered relative intensities of the gray- and white-matter structures on the MRI scans reflected replacement of the neurons with hypertrophic astrocytes and/or macrophages filled with storage material.