Abstract: A declining agricultural employment share is a key feature of economic development. Its main drivers are: improvements in agricultural technology combined with Engel’s law release resources from agriculture (“labor push”), and improvements in industrial technology attract labor out of agriculture (“labor pull”). We present a model with both channels and evaluate the importance using data on 12 industrialized countries since the nineteenth century. Results suggest that the “pull” channel dominated until 1920 and the “push” channel dominated after 1960. The “pull” channel mattered more in countries in early stages of the structural transformation. This contrasts with modeling choices in recent literature.