Indium tin oxide (ITO) nanoparticles with In/Sn = 9:1 (at.%) were synthesized by chemical coprecipitation method in an aqueous solution. The coprecipitate prepared at room temperature showed the crystal structure of indium oxide in X-ray diffraction when it was annealed at the temperature above 300 degrees C under air atmosphere. Reduction process was accomplished to improve the electrical property of ITO powder. Green ITO powder with particle sizes in the range of 20-30 nm was well dispersed by an addition of polyvinylpyrrolidone in an aqueous solution. The dispersibility of ITO sol solution was studied at different conditions by using ?-potential analyzer. Transmission electron microsopy (TEM) and energy dispersive X-ray spectrometer (EDS) were used to characterize morphology and composition of ITO nanoparticles.