The failure of oligodendrocytes to sustain repair of demyelinated axons contributes to the cumulative neurological disability which characterizes multiple sclerosis. In the rodent, transplanted neonatal glial progenitors efficiently remyelinate gliotoxic lesions. Proliferative bipotential progenitors are also present in the adult rat, but have not hitherto been identified in adult human tissue. Here we demonstrate cells in cultures of adult human temporal lobe which are morphologically and immunocytochemically identical to rate progenitors, are bipotential, and exhibit an astrocyte-driven proliferative response. The identification of an adult human oligodendrocyte progenitor is the first step towards developing interventional strategies for promoting repair of demyelinated lesions in patients with multiple sclerosis.