Abstract: This invention relates to a method of enhancing oil recovery from an underground reservoir containing oil. A gas which is miscible with oil at the temperature and pressure of injection is injected into the reservoir to displace oil. Injection is carried out in such a way as to make sure that a mixing zone is formed in the reservoir such that each fluid introduced is miscible with the fluid immediately preceding it and the fluid immediately following it. This is done by injecting small slugs of fluid miscible with, but different in composition from, the fluid adjacent to the perforated zone of the well. The injection of each slug is followed by a shut-in period to permit a mixing zone to establish itself.