We present three examples of key genes that function in arterial specification that have recently been implicated in lymphatic development; ephrinB2, FoxC2, and Notch. In arterial cell fate determination, Foxc2 regulates both Notch and Notch ligand expression. In turn, Notch signal activation in arteries drives expression of ephrinB2. It will be interesting to determine if the regulatory relationships between these pathways found in arterial development are relevant to understanding lymphatic development, that is, we ask whether arterial regulators are also key regulators of lymphatic development.