Abstarct: Over the past decades, nanoparticles were employed in various fields including medical science, medicine, cosmetic, and environmental remediation. Stabilization of these materials leads to enhance the efficiency and finding new applications for nanoparticles in different fields. In this research, the stabilization of iron oxide nanoparticles was carried out using rhamnolipid and saponin biosurfactants. The purity and particle size of the used iron oxide nanoparticles were 99.5% and 45nm respectively. The effect of important parameters including pH, retention time, nanoparticles concentration and biosurfactant concentration on the stabilization process were investigated. The optimum pH for stabilization using the biosurfactants was 7. According to the results, by increasing the retention time, the stabilization of nanoparticles using rhamnolipid was increased, while the retention time had no effect on stabilization process using saponin biosurfactant. Two chosen biosurfactants with concentration of 0.1% could stabilize nanoparticles with 50, 100 and 200ppm concentration. The reduction of biosurfactant concentration from 0.1% to 0.01% and eventually 0.001% caused the reduction of nanoparticles stabilization from 85% to 58% in the samples of 200ppm concentration of nanoparticles. Additionally, saponin biosurfactant with the low concentration (0.001%) showed the ability of stabilizing the nano particles in different concentrations (50, 100, and 200ppm). The results showed that the process of stabilization using saponin had more effect on increasing the diameter of nanoparticles in comparison with rhamnolipid. Increase in the zeta potential of nanoparticles stabilized with the biosurfactants (rhamnolipid=-38.7, saponin=-24.67) is an indication of stable suspension of nanoparticles in water.