A study has been performed to identify potential worldwide opportunities for early application Of CO2 sequestration. An early opportunity is defined as a high-purity CO2 point source, which can provide CO2 at low costs to oil or coal fields, where the CO2 is sequestered, and simultaneously enhance oil production (CO2-EOR) or coal bed methane production (CO2-ECBM). A Geographical Information System (GIS) was used to combine worldwide CO2 point sources and oil and coal fields. This resulted in 429 potential sourceoil field and 79 source-coal field combinations. A multi-criteria analysis (MCA), in which technical and socio-economic criteria are taken into account, was applied to rank the source-reservoir combinations generated by the GIS exercise. Some of the most promising cases were considered in more detail to select four illustrative cases for further study: two potential enhanced oil recovery (EOR) projects and two potential enhanced coal bed methane recovery (ECBM) projects. Case I consists of a hydrogen plant in Saudi Arabia, which could sequester 0.26 Mt/year CO2 in a depleted oil reservoir at a net saving of approximately 3 euro/t CO2. EOR case 2 is a hydrogen plant in California, USA, which has to be retrofitted in order to generate a pure CO2 stream. Approximately 0.28 Mt CO2 Could be stored annually. Mitigation costs have been estimated at 9-19 euro/t CO2, depending on the availability of steam for CO2 regeneration. In cases 3 and 4, circa 0.68 and 0.29 Mt CO2 from ammonia plants in China and Canada could be sequestered annually in coal fields for ECBM production at approximately 5 and 6 euro/t CO2, respectively. © 2004 Elsevier Ltd. All rights reserved.