A case of immunosuppressive measles (rubeola) encephalitis in a 12-year-old boy in remission from acute lymphoblastic leukemia is described. The patient presented with focal seizures which led to epilepsia partialis continua and then progressive obtundation. Magnetic resonance imaging revealed focal abnormalities, predominantly in the cortex, that on light and electron microscopic examination were demonstrated to be highly localized areas of neuronal loss, gliosis, and secondary Wallerian degeneration with paramyxovirus inclusions in the oligodendrocytes and surviving neurons.