Neuropilin is both a receptor for semaphorins, which are mediators of neuronal guidance, and for VEGF, an angiogenesis factor. While the function of neuropilin in the nervous system has been characterized, its role in angiogenesis is only beginning to be elucidated. This article reviews some of the structural and functional features of neuropilin and presents the experimental evidence showing that it is a mediator of angiogenesis. In particular, we show that neuropilin and its soluble isoforms regulate tumor angiogenesis and subsequent tumor growth