Similar to tumor metastases, endometriotic implants require neovascularization to establish, grow, and invade. The peritoneal environment is ideally suited to provide a proangiogenic milieu. Nevertheless, endometriotic lesions are found only in a minority of reproductive-age women (approximately 10%) with retrograde menstruation. In this paper, we review the major cytokines, growth factors, steroid hormones, and eicosanoids responsible for angiogenesis in endometriosis. We postulate that interference with angiogenic principles expressed in the peritoneum may constitute novel therapeutic opportunities for the prevention, amelioration, or treatment of pelvic endometriosis.