After the primary production period, water flooding is usually performed to recover more oil from reservoirs. However, water flooding recoveries are low from naturally fractured carbonate reservoirs, due in part to these reservoirs being mixed to oil-wet. Most of Iranian reservoirs are naturally fractured. Chemical process and especially surfactant flooding is an interested method because of its effect on interfacial tension (IFT) reduction and wettability alteration. Different surfactants are used for chemical flooding in the world but these chemical have high price and some detrimental effect on the environment. In this paper a new nonionic biosurfactant which is produced from the leaves of special tree called Zizyphus Spina-Christi is introduced. There is a hypothesis that this surfactant can be used in chemical flooding of fractured reservoirs because of very low cost and availability in Middle-East and Africa compared to other currently used surfactants. For this purpose surfactant is extracted from the leaves by spray dryer method. The pendant drop method is used to measure interfacial tension and critical micelle concentration (CMC) values. In order to investigate the effect of this surfactant on oil recovery two series of imbibition experiments are conducted on water-wet and oil-wet samples. It is observed that oil recovery is about ∼16 % OOIP (original oil-in-place) for oil-wet cores by using this surfactant. In the same test, no oil is produced with water due to high oil wettability. After adding surfactant to the water, the oil recovery about ∼7 % OOIP is obtained. Other test is done on water-wet cores which shows that addition of surfactant reduce the ultimate recovery from ∼35 % OOIP to ∼12.5 % OOIP. Reducing interfacial tension cause decrease in imbibition drive mechanism and lower the ultimate recovery. These results indicate that this new type of surfactant can meet the technical requirements as enhanced oil recovery (EOR) agent for chemical flooding.