Approximately 67% of human conceptuses die prenatally. Of these, a significant number involve a disorder of the lymphatic system. A small number of live-born children also exhibit congenital lymphatic malformations, including an estimated 60% of patients with Turner syndrome. These observations have prompted a search for the genetic and dysmorphologic basis and the different patterns of congenital lymphedema and associated anomalies. In this article, we attempt to summarize available pertinent information on congenital disorders of the lymphatic system and to propose a conceptual overview of lymphatic development.