Immiscible CO(2) injection is a potentially viable method of enhanced oil recovery (EOR) for medium oil reservoirs in southwestern Saskatchewan. The relatively high reservoir pressures could result in a large extent of CO(2) dissolution, significant oil viscosity reduction and oil swelling. Laboratory corefloods were used to compare the performance of different modes Of CO(2) injection into a medium-gravity oil system. The following methods were compared: injection of a single CO(2) slug chased by water, simultaneous injection of water/CO(2), and different water-alternating-gas (WAG) cycles. The results indicate that both a single CO(2) slug and the first WAG cycle in a series produced oil very efficiently, possibly owing to good gas/oil contact at the relatively high residual oil saturation at this stage. The simultaneous injection of water/CO(2) was not as effective as a single CO(2) slug, possibly because the co-injected water shielded the oil from being contacted by the gas. Among the four runs, a coreflood with four WAG cycles recovered the most incremental oil-20.58% initial oil in place (IOIP)-while the co-injection process produced the least (8.91% IOIP). This experimental study suggests that the immiscible CO(2) EOR process is viable for medium oil reservoirs with relatively high pressures, and that proper process application is important for maximizing additional oil production.