The International Atomic Energy Agency (IAEA) is one of the many bodies through which the United Nations serves their mandate towards Member States. Less widely known than others, the IAEA has a program on Human Health, which emerges from the Article II of the Statutes: “The Agency shall seek to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world”. It is delivered by the Division of Human Health, and its Section of Nuclear Medicine has the specific mission of fostering the application of nuclear medicine techniques in those diseases that may successfully be managed using radioisotopic applications. This mission is unique, as no other international organization, not even the WHO, has a similar role in promoting nuclear medicine in developing countries. In most cases, the Agency’s role is to provide support for human resource capacity building. In some other cases, when less developed countries are involved, support is also given by acquiring appropriate equipment, such as SPECT cameras; dose calibrators; radiation monitors; equipment for stress testing, etc) and supporting their maintenance. The long term objective of the subprogram in nuclear medicine focuses on enhancing Member States’ capability to address health needs by the use of both imaging and therapeutic applications, as well as of molecular biology techniques, whenever they provide a cost reduction or are complementary to conventional techniques. This is done by planning and implementing relevant projects, developed to address local or regional health problems, and by technology transfer with emphasis on problem solving capability. Different activities are run under this subprogram, like Coordinated Research Projects (CRPs); meetings of advisory experts and consultants to advise the Agency on specific topics; Publications and Manuals, including educational material, and creation of databases. The organisation of training courses and workshops, selection of technical experts, evaluation of fellowship requests and undertaking technical missions are among the important activities at the national level. A large portion of these are related to the so-called Technical Cooperation (TC) Program whose beneficiaries are patients, practitioners of medicine, life science researchers, health administrators, planners and decision makers in Governments. In that context, the role of the professionals of the Nuclear Medicine Section is to appraise TC project requests as it would be expected from an independent “referee”, although very often a more active role in reformulating projects to make them feasible is required. Since sustainability remains one of the most relevant issues to be addressed for these projects to be successful in the long term, considerable attention is given to human resource capacity building through education and training activities. To this purpose, training courses are organized, including the preparation of syllabi, selection of lecturers and students, in addition to undertaking considerable active lecturing tasks. The IAEA is also involved in research activities through its CRPs, whose outcomes will benefit Member States, participating scientists and institutions as well as the international scientific community. Often, the results quickly become of direct benefit to groups outside of the scientific community, for example to patients if the research is carried out in the human health program of the Agency.