HIV and AIDS, tuberculosis, and malaria, besides presenting a large mortality and morbidity burden in developing countries, are also responsible for poor economic development. In the past international agencies devoted resources and efforts to control malaria and other diseases without taking into account health-system performance and sustainability. Even assuming that the Global Fund to Fight AIDS, Tuberculosis, and Malaria (GFATM)--a recent international initiative--would provide the necessary funds, a poorly performing health-care system will not be able to use these funds optimally. Moreover, even if all interventions are cost-effective, their impact on mortality and morbidity will only be marginal if access to proper care is not guaranteed. It is the responsibility of scientists and health managers to highlight to donor agencies the importance of an accessible and well functioning health-care system at all levels for the control of specific diseases.