Organization of Petroleum Exporting Countries. An intergovernmental organization of 12 oil-exporting developing countries, which coordinates and unifies the petroleum policies of its member states. It works on stabilizing oil markets to secure an efficient, economic and regular supply of petroleum to consumers, a steady income to producers and a fair return on capital to investors in the petroleum industry. OPEC was founded in 1960 in Baghdad, Iraq, by four Middle Eastern countries (Iran, Iraq, Kuwait and Saudi Arabia) and Venezuela. OPEC countries work together in UNFCCC negotiations, putting forward their common interests, and their perspective on climate change measures and their impact on OPEC countries.