The primary mission of IAEA is to promote the pacific use of nuclear energy and to support the development of useful applications of radiation in various fields ranging from food and environment, conservation of cultural heritage and healthcare. In particular, the Agency has been constantly involved in assisting Member States (MS) to implement their diagnostic and therapeutic procedures based on the use of radiopharmaceuticals. This category of radioactive products is designed to target specific biological substrates for obtaining diagnostic information or for delivering a cytotoxic dose to diseased tissues, thus eliciting a therapeutic effect. The number of IAEA projects on radiopharmaceuticals is impressive as they cover almost completely the most relevant aspects of the use of radioactive substances for medicine. Essentially, there are two different types of projects: (a) Technical Coordinated Project aimed at supporting (MS) to achieve the most advanced methods and technologies in molecular imaging and radionuclide therapy, and (b) Coordinated Research Projects focused on relevant current research subjects on radiopharmaceuticals and aimed at promoting the collaboration between research groups around the world. In this lecture, a short overview of the main IAEA activities in the field of radiopharmaceuticals and of their impact on the advancement of both research and patient's care in MS will be illustrated.