[en] One of the current important issues of nuclear power is the long lived radioactive waste toxicity problem. The sharpness of this problem could be considerably reduced if, during energy production, there was the possibility to incinerate at least the most toxic radioactive isotopes (long lived fission products and minor actinides). The combination of external intensive neutron sources with facilities containing nuclear fuel, so-called hybrid systems, are under investigation in several countries. The surplus of neutrons in such systems may be used to convert most of the long lived radioactive nuclides into isotopes having a shorter lifetime. Currently, an increasing number of groups are entering this field of research. There is clearly a need for co-originated their efforts, and also for the exchange of information from nationally or internationally co-ordinated activities. Consideration of the advantages of hybrid systems, and the wide field of interdisciplinary areas of research involved, show the need for an international co-operation in this novel R and D area. The International Atomic Energy Agency has maintained an active interest in advanced nuclear technology related to accelerator driven systems (ADS), and related activities have been carried out within the framework of its programme on emerging nuclear energy systems. After thorough analyses of the outcomes of several international forums and recommendations of the IAEA Technical Committee Meeting on Feasibility and Motivation for Hybrid Concepts for Nuclear Energy Generation and Transmutation (Madrid, Spain, 1997), the IAEA conducted an Advisory Group Meeting on Review of National Accelerator Driven System Programmes in Taejon, Republic of Korea, from 1 to 4 November 1999. The scope of the meeting included review of the current R and D programmes in the Member States and the assessment of the progress in the development of hybrid concepts. The programme of the AGM included the following topics: Comprehensive presentations from groups conducting the most active research and development projects (Prof. Rubbia (on behalf of the '3 countries initiative': French-Italian-Spanish collaboration), CERN, CEA, JAERI, USA (LANL, BNL, LLNL, ANL, ONL), EC ADS-project (TARC, IABAT), Russian Federation. The presentations centered on the following issues: General issues and motivations: national/international views, specifically: Why is ADS needed for the country; Role of ADS in future nuclear cycles and waste management; General safety issues and requirements of ADS; Public acceptance; ADS Technology; Accelerators for ADTT (cyclotrons and linacs); Specific requirements and features of ADS accelerators; Reliability of operation; Design efficiency; Development of ADS-oriented codes and methods; Benchmark reports; Experiments and validation of codes; Deterministic and Monte-Carlo codes; Coupling of high and low energy transport; Static and dynamic methods for subcritical systems; Spallation and fission product modeling; Targets and nuclear assemblies for ADS; ADS Targets (solid and liquid); Damage to materials (Materials irradiation in Proton field, High energy neutron field, Temperature/shock effects, etc., experiments related to Technology of heavy liquid metals, Thermohydraulics, Corrosion); Experiments (Hg target experiments at BNL; Subcritical cores, Fuels and fuel processes, Molten salt reactors)