Demyelinated CNS axons can be remyelinated by Schwann cells. A recent study concluded that with time Schwann cell remyelination is replaced by oligodendrocyte remyelination [9]. To examine this, the extent of Schwann cell and oligodendrocyte remyelination at 4, 6.5 and 24 weeks was determined for ethidium bromide lesions made in the spinal cords of rats. Although the extent of oligoden-drocyte remyelination increased with time there was no significant change in the amount of Schwann cell remyelination. This indicates that Schwann cell remyelination is stable and is not replaced by oligodendrocyte remyelination.