The present article analyzes the role of the Union of South American Nations (UNASUR) national institutes of health since their creation at the beginning of the 20th century up until the present time. It postulates that the national institutes of health are in a position to play a strategic role in generating knowledge and evidence to facilitate decision-making through monitoring and research on the social determinants of health and health inequities. To explore this hypothesis, the national institutes of health are analyzed in the context of the current global scenario, which is generating increased social inequalities, thus leading in turn to serious inequities in health conditions. The article proposes a new model of health promotion, disease prevention, and health care, where necessary, as well as policies and intersectoral actions that address these social determinants. In this new stage, the UNASUR national institutes of health should play a significant strategic role in identifying and analyzing correlations between patterns of production and consumption, social divisions that exist in the territory, conditions of development, and the health of their populations. These national institutes of health are members of the UNASUR Network of National Institutes of Health (RINS-UNASUR). The literature on their creation, drawn from the Network's websites and the proceedings of its meetings and seminars, is reviewed. Given that the current globalized development model is generating enormous social inequalities, by definition, the proposed hypothesis is that the national institutes of health should assume a much broader role in addressing the consequent inequities in the health of the population, complementing their traditional activities with this new strategic role. Without a major reduction in the existing social inequalities and economic inequities, it will be impossible to make significant improvements in health in a democratic manner.