It is now widely accepted that the developing world needs to invest in science and technology or risk falling behind as the technology gap between the North and South widens. However, these investments must be balanced by continued investment in basic population-wide services, such as healthcare and water supply and sanitation. Achieving this balance is a matter of ongoing debate in policy circles, and leaders and policy-makers in developing countries often have to make difficult decisions that pit investment in new technologies and capacity-building in science and technology against basic population-wide services such as healthcare and water supply and sanitation. The tension is underscored by evidence which suggests that rapidly industrializing economies, like in China, India and Brazil, are actually experiencing a rise in economic and health disparities among their populations. The fact that poor people in an industrializing country must fall behind while the rest of the country marches ahead does not have to be an inevitable outcome of industrialization. This article shows that science and technology can make an important and vital contribution to development, using public health as an example. It suggests the need to focus investments in science and technology in such a way that they can have a positive impact on public health. For instance, the use of simple, hand-held molecular diagnostic tools can help unskilled health workers rapidly and accurately diagnose diseases, thus helping to reduce healthcare costs due to delayed or incorrect diagnoses. Recombinant vaccines can mitigate the risk of infection associated with live or attenuated vaccines, while needle-less delivery methods can help contain the spread of blood-borne infections. Critical to making technology investments work for population health are government policies and strategies that align public health goals and technology priorities. Such policies can include cross-sectoral training programs to improve dialogue between the technology and health sectors, setting up technology transfer cells to increase commercialization of health research relevant to local needs, and leveraging the phenomenon of low-margin high-volume marketing for health products.