As they mature, thymocytes migrate to specific regions of the thymus, interact with different types of stromal cells, and thereby receive signals for survival, differentiation, or death. Despite its importance, the molecular control of thymocyte trafficking remains poorly understood. Chemokines and their receptors probably control the homing of T cell progenitors to the thymus, their intrathymic migration, and exit to the periphery. Certain chemokines are abundant in the thymus, and their receptors are expressed during distinct developmental stages. Below, we discuss recent studies of chemokines and their receptors in the thymus, speculating on their function in the frame work of thymocyte trafficking.