AbstractIn this paper, a new plant based natural cationic surfactant, named Seidlitzia rosmarinus, is introduced, and the viability of using this natural surfactant as an alternate to synthetic surfactants for chemical enhanced oil recovery is investigated. For this purpose, the interfacial tension values between natural surfactant solution and oil are measured by using the pendant drop method. The results show that Seidlitzia rosmarinus decreased the interfacial tension values from 32 to 9 mN/m. Results confirm the fair surface activity of Seidlitzia rosmarinus in comparison with other natural and synthetic surfactants. Accordingly, this natural surfactant can be used as a surfactant for chemical enhanced oil recovery.