A Lubricant is a substance which is used to reduce generated heat and friction between the moving surfaces in contact. The improvement of wear and friction properties of lubricating materials is important because they are widely used in industry and in mechanical machineries. In this research, impacts of addition of nanoparticles on stability of lubricant and wear and friction behavior of base oil are investigated. The abrasion is studied using a pin on disk wear testing device and normal St 37 steel disk in the presence of different lubricant samples. The nanoparticles used were Cuo, Zno, and Fe 3 o 4 and the lubricant was SN 500 base oil. Nanoparticles were added to the base oil in four different weight percentages and their wear and friction behavior on normal steel disks was compared with each other. Abrasion tests on normal steel disks using nanofluid samples were conducted by applying a load of 60 N and a speed of 30 meters per second and at a distance of 100 meters . Cuo and Zno nanoparticles were mixed with base oil in 0.1, 0.5, 1, and 1.5 wt%, and Fe 3 o 4 nanoparticles were added in 0.1, 0.5, and 1 wt%. Results showed that nanofluid samples with 0.5 wt % Cuo nanoparticles, 0.1 wt% Zno nanoparticles, and 0.1 wt % Fe 3 o 4 nanoparticles lowest friction was observed. Weight loss of disks recorded after the test was consistent with the results of pin on disk wear test charts. Non-ionic surfactants nonylphenol 10 and coconut fatty acid were used to improve the stability of nanofluid samples. 0.5 wt% of each surfactant was added to the nanofluid and by studying viscosity changes over time nanofluid stability was studied. Among the three nanofluid samples that demonstrated the lowest friction, the nanofluid with Fe 3 O 4 showed highest instability. AFM surface analysis was performed on disks with lowest friction carried to lowest friction showed that addition of all nanoparticles to base oil effectively reduces friction. Key word; Trbology,wear and Friction ,Nanoparticle Cuo،Zno و Fe 3 O 4 ,Base oil SN 500