Notch receptors play crucial roles in many cellular differentiation programs. In addition to a more classical role for Notch in keeping cells in an undifferentiated state, a recent paper has provided clear evidence that Notch signaling is a powerful means of turning adult CNS precursor cells into astrocytes. This work, combined with other reports from the developing CNS, retina and the PNS, demonstrates a role for Notch in gliogenesis. These findings can also be linked to novel insights into the function of proneural basic helix–loop–helix proteins in astrocytic differentiation.