Various types of cells in the human spinal cord and brain, status spongiosus of the white matter of the spinal cord were studied by electron microscopy; the comparison was made to the status spongiosus in monkeys with experimental amyotrophic leukospongiosis. The alterations in the motor neurons of the spinal cord, pyramidal neurons of the brain hemisphere cortex and cerebellum ganglious neurocytes were revealed. Changes in some cells (astrocytes, olygodendrocytes) were characterized. The possibility of a primary axon damage in this disease is discussed.