In the developing nervous system, special cells called ‘neural crest progenitors’ are born and develop into most components of the peripheral nervous system (PNS). In this work we identified a protein, called Yes-associated-protein (YAP), which is necessary and sufficient for the onset of migration of neural crest progenitors and for their subsequent development. Furthermore, we characterized the molecular pathway by which YAP exerts its activity. This work advances our understanding of the molecular network responsible for the ontogeny of the PNS.