The optimum range of power system transmission and distribution (T and D) losses is between 5 to 10 per cent. Recent surveys in selected developing coun tries of Asia and the Pacific region have shown that, in many of these coun tries, system losses are far beyond this tolerable limit. About 48 per cent of the countries surveyed lost 16 per cent or more of their elec tricty generation in the T and D system. Thus there is scope for increasing effective supplies from existing generating capacities by reducing these losses in many developing countries of the Economic and Social Commissi on for Asia and the Pacific (ESCAP) region. The amounts by which system losses can be reduced are subject to various factors within each country. Optimizing the utilization of each country's generated output more fully and effectively should receive greater emphasis. Such a strategy could increase effective supplies sooner than alternative possibilities. The Korea Electric Power Corporation (KEPCO) has attained a remarkable achievement in reducing its system losses in a relatively short period of time. Devel opin g counties, of the ESCAP region, and particularly their electric utility boards/ enterprises, showed keen interest in learning from the experience of KEPCO. ESCAP, in collab oration with the Government of the Republic of Korea successfully organized two training courses at KEPC0, Seoul within the framework of implemenation of Regional Energy Development Programme (REDP), funded by the United Nations Developmen t Programme (UNDP). The first training course was held in May 1988 and the sec ond in May/June 1989.