Alkaline-surfactant-polymer (ASP) flooding is a combination process in which alkali, surfactant and polymer are injected at the same slug. Because of the synergy of these three components, ASP is the current world-wide focus of research and field trial in chemical enhanced oil recovery. This paper is to provide a comprehensive review of the ASP process. The reviewed topics include the following: • ASP synergy and its EOR mechanisms • Screening criteria • Laboratory work • Numerical simulation work • Summary of pilots and large-scale applications • Project economics • Chemicals used • Water quality • Salinity gradient • Mobility control requirement • Problems associated with ASP flooding In addition to the comprehensive review, future developments are also discussed. Data and analyzed results presented in this review will help oil operators save research and pilot costs, and to build their confidence to execute and expedite their ASP projects.