Coronary artery development is a complex vasculogenic process that begins shortly after heart looping. Coronary vasculogenesis is regulated by the myocardium, but is spatially and temporally dependent on the epicardium and its precursor, the proepicardial organ, for the provision of coronary vascular progenitor cells. Better understanding of the mechanisms of coronary artery development may clarify mechanisms of disease and suggest new potential therapies for disorders of the coronary vasculature.