Inhibition of angiogenesis is regarded as a promising tool in the treatment of diseases such as cancer, arthritis and atherosclerosis. This fact has led to the search for novel endogenous or synthetic angiogenesis inhibitors. Recently, antiangiogenic properties were ascribed to an endogenous molecule that until only recently was known for its antibacterial effects. This molecule, bactericidal/permeability-increasing protein (BPI), that was discovered as a bacterial permeabilizing and lipopolysaccharide-neutralizing protein, was found to inhibit angiogenesis by specific induction of apoptosis in endothelial cells. This paper gives a short introduction on angiogenesis and reviews the current knowledge on BPI as an angiogenesis inhibitor. In addition, the issue of commonality between antibacterial and antiangiogenic functions will be addressed.