This mini-review is a summary of most recent data on the morphology, physiology and pathology of the vascular endothelium. This article presents the results of the rapidly growing research work on endothelial cells. We discuss how these cells work as an "organ" and their importance and function in the body. Endothelial cells have pluripotent functions both in normal and pathological conditions. The article emphasizes the discoveries and roles of receptors present on the endothelial cell surface and the potential of their use as recognition sites in the treatment of various diseases including cancer.