Cells of brain tissue of rabbits, rats and mice were dissociated and glial cells, neuronal perikarya and synaptosomes were separated by centrifugation on discontinuous Ficol gradients. HSV was shown to attach well to rat and rabbit glial cells and synaptosomes but not to neuronal perikarya. Of intracerebrally infected mice the fractions with glial cells contained the infective virus. The interactions between HSV and neuronal cells and the implication of the observations on the HSV infection of the nervous system are discussed.