An effective parameter in the miscible-CO 2 enhanced oil recovery procedure is the minimum miscibility pressure (MMP) defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve miscibility at a given temperature. Flue gases released from power plants can provide an available source of CO 2, which would otherwise be emitted to the atmosphere, for injection into a reservoir. However, the costs related to gas extraction from flue gases is potentially high. Hence, greater understanding the role of impurities in miscibility characteristics between CO 2 and reservoir fluids helps to establish which impurities are tolerable and which are not. In this study, we simulate the effects of the impurities nitrogen (N 2), methane (C 1), ethane (C 2) and propane (C 3) on CO 2 MMP. The simulation results reveal that, as an impurity, nitrogen increases CO 2-oil MMP more so than methane. On the other hand, increasing the propane (C 3) content can lead to a significant decrease in CO 2 MMP, whereas varying the concentrations of ethane (C 2) does not have a significant effect on the minimum miscibility pressure of reservoir crude oil and CO 2 gas. The novel relationships established are particularly valuable in circumstances where MMP experimental data are not available. Keywords EOR exploiting impure flue gases Á CO 2-crude oil minimum miscibility pressure (MMP) Á Impact of gas impurities on MMP