Retinopathy of prematurity is marked by the proliferative vascularization of the retina in preterm babies. An understanding of the molecular pathogenesis of ROP provides the basis for identifying novel therapeutic targets for treatment. Using the mouse model of oxygen-induced retinopathy, the roles of the hypoxia induced factors vascular endothelial growth factor and erythropoietin as well as the maternally derived factors insulin-like growth factor-1 and omega-3 polyunsaturated fatty acids have begun to be elucidated. Understanding the phase specific effects of these factors will serve to guide the development of non destructive treatments for ROP and for other ischemic retinopathies including diabetic retinopathy and neovascular age-related macular degeneration.