Four patients with well documented Reye syndrome were examined with noncontrast computed tomography. Acute findings are those of diffuse cerebral edema with low density in deep white matter, increased gray-white matter differentiation, and evidence of secondary ventricular compression. The diffuse nature of the changes is unlike the more focal pattern often seen in true viral encephalitis. Residual changes after severe diseases are those of nonspecific cerebral degeneration and are most pronounced in the frontal lobes. Atrophic ventricular dilatation was observed in two cases. Computed tomography findings correlate with all known pathologic studies and with the subsequent clinical courses in the patients examined.