[en] The application of radiation in human health, for both diagnosis and treatment of disease, is an important component of the work of the IAEA. The responsibility for the increasingly technical aspects of this work is undertaken by the medical physicist. To ensure good practice in this vital area, structured clinical training programmes are required to complement academic learning. This publication is intended to be a guide to the practical implementation of such a programme for nuclear medicine. There is a general and growing awareness that radiation medicine is increasingly dependent on well trained medical physicists who are based in a clinical setting. However an analysis of the availability of medical physicists indicates a large shortfall of qualified and capable professionals. This is particularly evident in developing countries. While strategies to increase educational opportunities are critical to such countries, the need for guidance on structured clinical training was recognized by the members of the Regional Cooperative Agreement for Research, Development and Training related to Nuclear Science and Technology (RCA) for the Asia-Pacific region. Consequently, a technical cooperation regional project (RAS6038) under the RCA programme was formulated to address this need in this region by developing suitable material and establishing its viability. Development of a clinical training guide for medical physicists specialising in nuclear medicine was started in 2009 with the appointment of a core drafting committee of regional and international experts. The publication drew on the experience of clinical training in Australia, Croatia and Sweden and was moderated by physicists working in the Asian region. The present publication follows the approach of earlier IAEA publications in the Training Course Series, specifically Nos 37 and 47, Clinical Training of Medical Physicists Specializing in Radiation Oncology and Clinical Training of Medical Physicists Specializing in Diagnostic Radiology, respectively. This approach to clinical training has been successfully tested in Thailand, with three other Member States currently undergoing testing, and is believed to be generally applicable to the medical physics community in general