Nanocrystalline Sb-doped SnO2 particles were prepared by sol-gel and their particle growth was controlled by niobium oxide. In the present synthesis, SnCl4 and SbCl3, as precursors, were dissolved and hydrolyzed in ethylene glycol at 80-120 degreesC, and further 0.1 mol.- % Nb2O5 through its precursor NbCl5 was mixed to the above solution. The mixture was then dried at 120-150 degreesC and calcinated at 600 degreesC for 2 hours. By XRD and TEM, Sb-doped SnO2 nanoparticles were highly crystalline and their mean crystal size was ca. 10-20 nm with narrow particle size distribution. As the addition of antimony increased, the crystallinity and particle size distribution of SnO2 particles had the trend to decrease.