Anthropogenic effects on climate can be mitigated through various measures, among them being CO2 sequestration in geological media. Geological sinks for CO2 do not really need any major technological development because the technology has already been developed and applied by the upstream energy industry for hydrocarbon exploration and production. The challenge is rather to identify the best methods and sites for long term CO2 sequestration. There are various ways to sequester CO2 in geological media: utilization in EOR operations, disposal in disused oil and gas reservoirs, replacement of methane in coal beds, injection in deep saline aquifers and storage in salt caverns. Several criteria have to be considered when evaluating the potential of a sedimentary basin for CO2 sequestration: its tectonic setting and geology, the basin geothermal regime, the hydrodynamic regime of formation waters, the hydrocarbon potential and basin maturity, economic aspects relating to access and infrastructure and socio-political conditions. The range of sedimentary basins suitable for CO2 sequestration is significantly reduced if these criteria and climatic conditions, accessibility, infrastructure and cost of CO2 capture and injection are taken into account. A systematic approach is proposed for the assessment and selection of method and sites for CO2 sequestration in geological media. (C) 2000 Elsevier Science Ltd. All rights reserved.