In "Just Health", Norman Daniels makes a strong argument for obligations of mutual assistance to fulfill the right to health at the national level and challenges readers to develop arguments supporting obligations of mutual assistance at the global level. In this paper, we argue that there is global responsibility for global health and that there are obligations of justice (beyond charity) to help fulfill (not merely respect or even protect) the right to health in other countries; these we call obligations of global health justice. We show how international human rights law affirms obligations of global health justice - beyond national obligations and beyond obligations of charity - and assert that the human rights approach provides guidance on delineating the relationship between national and global responsibility for fulfilling the core obligations that arise from socioeconomic human rights and addressing global health inequities. We further argue that new ways of providing international assistance, originating from the global HIV/AIDS response, demonstrate the feasibility of improving health outcomes through exogenous efforts and that obligations of global health justice thus carry much weight: the weight of lives not saved. The global response to the HIV/AIDS pandemic has led to the emergence of a new international health assistance paradigm, and the Global Fund to fight AIDS, Tuberculosis and Malaria is, we suggest, an embryonic form of this new paradigm. We conclude that agreements on several common parameters delineating global and national responsibility for global health can advance the movement towards a global institution for the distribution of health-related goods.