In this paper, indium tin oxide (ITO) nanoparticles has been prepared by chemical methods under given conditions with solution of indium chloride (InCl3·4H2O), tin chloride (SnCl4·5H2O) in ammonia solution. The samples were characterized by X-ray Diffraction (XRD) and scanning electron microscopy (SEM) analyses after heat treatments. The SEM results showed that, the size of the ITO particles prepared by co-precipitation route decreased to 46 nm whereas the size of the ITO prepared by hydrothermal and pechini sol-gel methods increased to 1 micron. The XRD patterns revealed that, the size of crystallite ITO particles prepared by sol-gel and hydrothermal methods increased. Finally the intensity ratio of I400/I222 had a decrease of 21.67 percent for ITO prepared by hydrothermal method.