[en] The international effort (UNIDO, ILAC, BIPM, etc.) to establish a functional infrastructure for metrology and accreditation in many developing countries needs to be complemented by assistance to implement high quality practices and high quality output by service providers and producers in the respective countries. Knowledge of how to approach QA systems that justify a formal accreditation is available in only a few countries and the dissemination of know how and development of skills is needed bottom up from the working level of laboratories and institutes. Awareness building, convincing of management, introduction of good management practices, technical expertise and good documentation will lead to the creation of a quality culture that assures a sustainability and inherent development of quality practices as a prerequisite of economic success. Quality assurance and quality control can be used as a valuable management tool and is a prerequisite for international trade and information exchange. This publication tries to assist quality managers, Laboratory Managers and staff involved in setting up a QA/QC system in a nuclear analytical laboratory to take appropriate action to start and complete the necessary steps for a successful quality system for ultimate national accreditation. This guidebook contributes to a better understanding of the basic ideas behind ISO/IEC 17025, the international standard for 'General requirements for the competence of testing and calibration laboratories'. It provides basic information and detailed explanation about the establishment of the QC system in analytical and nuclear analytical laboratories. It is a proper training material for training of trainers and makes managers with QC management and implementation familiar. This training material aims to facilitate the implementation of internationally accepted quality principles and to promote attempts by Member States' laboratories to obtain accreditation for nuclear analytical techniques. The methodology provided is appropriate for: (a) Analysis of radionuclides as in alpha, beta, and gamma spectrometry for environmental and human-made radioactivity investigations; (b) Analysis of trace, minor and major elements using nuclear and related analytical techniques such as neutron activation analysis, X ray fluorescence, PIXE, etc. This training guidebook can be used by staff of analytical laboratories as a starting kit to better understand the quality assurance and quality control principles as prescribed in the ISO 17025 standard. It follows a logical order related to practical laboratory work rather than the formal clauses as given by the standard. It can be used as a stand alone textbook. However, in some cases, cross-reference is given to the ISO 17025 clauses hence it is recommended to consult the ISO standard for exact wording of specific requirements