A surfactant waterflooding process for the recovery of oil from subterranean oil reservoirs in which a water-soluble polyalkylene oxide is employed as a sacrificial agent in order to retard adsorption of the surfactant. An aqueous pretreatment slug is injected which contains a water-soluble polyalkylene oxide sacrificial agent having a molecular weight of at least 1200. Thereafter an aqueous slug containing a surfactant exhibiting a lower molecular weight than that of the polyalkylene oxide sacrificial agent is injected. The surfactant slug may also contain a polyalkylene oxide sacrificial agent as described above. In this case, concentration of sacrificial agent in the surfactant slug normally is lower than the concentration in the pretreatment slug.