This study is based on applying of iron nanoparticles to simultaneously removal of heavy metal ions, nickel(II) and cobalt(II), which play an important role in waters pollution. For this purpose 0.03 g of iron nanoparticles was added to a solution containing cobalt and nickel cations and then the ultrasonic waves was used to suspend the reaction minture(nonparticles + Ni(II) + Co(II)) in the solution. The applied ultrasonic waves have an important role for breaking nanoclusters and enhancing the surface to volume ratio of them, which leads to more removal of nickel and cobalt ions from water by surface adsorption and reduction phenomena on the iron nanoparticles. The observation show that the total of 15-20 mg L -1 and 23-27 mg L -1 of nickel and cobalt ions were removed respectively, and the removal range was more than range in the previous methods that reported for removal of heavy metals by iron nanoparticles and also this procedure is economical. On the other hand, the simultaneous presence of cobalt ions in the vicinity of nickel ions leads to enhancing the removal efficiency of nickel ions by nanoparticles to about 27-32 mg mL -1 which is one of the interting advantages of this study. Finally, the removal extent of nickel and cobalt were measured by nanoparticles which were aged in water for a period of time, and the results showed that the removal efficiency was decreased to 13-18 and 10-15 mg L -1 for nickel and cobalt, respectively, which may be due to several forms of iron oxides.