A case of fulminant subacute myelooptico-neuropathy that occurred in a native American women following pneumonitis instead of the usual gastrointestinal dysfunction is reported. After the acute stage, which left the patient paraplegic and partially blind, she suffered an exacerbation which resulted in her death 11 months after the onset of illness. Autopsy disclosed symmetric optic and spinal demyelination. Neutralizing antibody titer against subacute, myelo-optico-neuropathy virus was determined on postmortem serum 3 1/2 years after death and found significantly elevated.