It has been shown that one kind of poly silicon particles with sizes ranging from 10–500 nm, can be used in oilfields to enhance the oil recovery of water injection by 15–20%. The contributing mechanism might be reducing the interfacial tension which appears through improving relative permeability of the oil-phase. However, fundamental understanding of how hysteretic behavior of relative permeability curves affected by nanosilica particles remains a topic of debate in the literature. In this study, water as well as water dispersed nanosilica particles floods was performed on sandstone rock sample saturated by light crude oil supplied from one of Iranian oil reservoir, and the relative permeability curves for both oil and water/ water dispersed nanosilica particles phases were determined for two successive cycles of imbibitions/drainage processes. The results revealed that the hysteresis in relative permeability of both oil and water phases decreased as the dispersed silica nano particles were used in the tests, and the hysteretic behavior of relative permeability curves decreased as the injection proceeds into the 2nd cycle of injection. Moreover, the relative permeability of non-wetting phase changes significantly while the changes for wetting phase is not much considerable. This work illustrates for the first time the role of dispersed silica particles on hysteretic trend of two-phase oil-water relative permeability curves.