The lymphatic vascular system is important for immune surveillance, tissue fluid homeostasis and fat absorption, and is involved in many pathological processes, including tumor metastasis and lymphedema. The recent success in the isolation of lymphatic endothelial cells has shed light on their molecular characteristics. Lymphatic commitment and growth during embryonic development is dependent on the activities of the homeodomain transcription factor Prox-1 and vascular endothelial growth factor-C (VEGF-C). VEGF-C and VEGF-D are involved in adult inflammation-associated lymphangiogenesis, wound healing and tumor metastasis. Administration of lymphangiogenic growth factors or their antagonists provides the possibility of targeting lymphatic vessels in human disease.