Over the past 8 years, the International Association of Oil and Gas Producers (OGP) has collected environmental information from its member companies on an annual basis. The ultimate aim of this project is to provide a representative statement on the environmental performance of the upstream oil and gas industry. Subsidiary objectives are to provide a basis for individual member companies to compare their environmental performance and to demonstrate the industry’s wish for greater transparency concerning its activities. This will help them to identify better and more efficient ways of operating. Environmental information relating to emissions and discharges is collected under the following five categories: Emissions to air; Aqueous discharges; Discharges of non-aqueous drilling fluids on cuttings; Accidental spillages of oil and chemicals; and Energy efficiency Data are collected annually for each of the categories above, on the basis of a set of definitions agreed by the OGP membership. The definitions are provided via a Users’ Guide that is reviewed at regular intervals and updated to reflect improvements in reporting and to provide additional clarification. Quality assurance is an integral part of the reporting process and contributing companies are asked to provide information on the quality assurance systems that underpin their data submissions. A report of activities in 2003, 2004 and 2005 and summary reports for activities in 2001 and 2002 have been published previously.