Cell movement is a fascinating feature of animal development. Genetic approaches have recently led to the identification of regulatory proteins required for specific cell migrations in development of the mouse, nematode and fruit fly. Here, I focus on two model systems for genetic studies of cell migration during Drosophila development: migration of follicle cells in the ovary and migration of tracheal cells in the embryo. Mutations that affect these migrations have allowed the identification of transcription factors and an FGF receptor homolog as important regulators of cell migration. Signaling through receptor tyrosine kinases may be a general mechanism for the regulation of cell movement in development and in metastasis.