In this investigation, silver nanoparticles (AgNP) were evaluated as a nematicidal substance in laboratory and screenhouse experiments. Second infective juveniles (IJ2) of Meloidogyne incognita were exposed to AgNP in water at with the consternations of 20, 40, 200, 500, and 1500 ppm/ml. the concentration of 200 ppm caused 52% mortality at the third day, while 500 ppm caused 51% mortality after one day and 64%, 82% after the second and the final day, respectively. The most effective concentration was 1500 ppm which caused 89%, 93, and 96.5 %, respectively. In the screen house experiment, all the concentrations of AgNP inhibited the nematode growth (gall and egg formation and final population) and eggs hatchability. However the high concentrations of 200 ppm, 500 ppm, and 1500 ppm were more significant in their effect. The application of AgNP didn't show toxic effect on the plant growth or the free living nematodes. It can be concluded that, the laboratory assays to the nematicidal effect of AgNP, and the screenhouse evaluation demonstrated that, its nano silver may be a more safety alternative method to control root knot nematodes.