Enhanced oil recovery (EOR) technology coupled with underground carbon dioxide sequestration is introduced. CO₂ can be injected into an oil reservoir in order to enhance oil production rate and CO₂ EOR can be turned into CCS in a long term sense. Coupling CO₂ EOR with CCS may secure a large scale and consistent CO₂ source for EOR, and the CO₂ EOR can bring an additional economic benefit for CCS, since the benefit from enhanced oil production by CO₂ EOR will compensate costs for CCS implementation. In this paper, we introduced the characteristics of CO₂ EOR technology and its market prospect, and reviewed the Weyburn CO₂ EOR project which is the first large-scale CO₂ EOR case utilizing an anthropogenic CO₂ source. We also introduced geotechnical elements for a successful and economical implementation of CO₂ EOR with CCS and they were a miscroseismic monitoring during and after injection of CO₂, and determination of minimum miscible pressure (MMP) and maximum injection pressure (MIP) of CO₂.