The large oil and natural gas resource base and the greater competitiveness of conventional energy supply technologies based on oil and gas is a key energy characteristic in the countries of the GCC. Until today, mostly pilot and research Renewable Energy Sources (RES) and Rational Use of Energy (RUE) activities were conducted. However, these countries seem to be ready to take a more active part in the development of environmental friendly energy technologies. RES are expected to play a greater role in the future based on the rich natural potential of the region. In addition, appropriate efforts to formulate strategic RUE policies are initiated for assuring buildings sustainability and providing guidelines for future architecture. In this context, GCC countries are realizing the inevitability of putting climate change issues on the top of the list of priorities in the process of economic and social development. This paper includes an analytical review of the current RES and RUE development status in the GCC region, giving special emphasis to the business opportunities that the region offers for regional and international companies involved in this market. (c) 2005 Elsevier Ltd. All rights reserved.