Technological innovation is often associated with promising improvement of life conditions and health. However, potential benefits are largely dependent on affordability, availability and accessibility and too often technology fails to attain those promises on a global scale. The possibilities offered by nanotechnologies to develop more cost-effective interventions in relation to diagnosis, treatment and follow-up of diseases, as well as to advance in the fields of energy, agriculture and water treatment, are considered from a global health perspective. Besides concerns related to safety, the main challenge rests in avoiding that the introduction of nanotechnologies further increasing existing inequities in health and access to appropriate services. The main responsibility in facing this challenge lies with national governments and international organizations, with new emerging roles for industry and academia which pose a number of questions of ethical relevance. We identify the danger linked to a too narrow bio-medical approach and argue that the development of a stronger "global conscience," fostered by open knowledge sharing and wide information about potential benefits and harm to public health, represents a moral imperative and a critical element for the success of any technological innovation in effectively contributing to the improvement of global health.