Nanopowders of antimony-doped tin oxide have been prepared by a hydrothermal method with Sb dopant concentration changed from 0 to 3 at.%. The hydrothermal treatment was carried out from 180 to 220 °C in 24 h. The structure and morphology of the product were characterized by x-ray diffraction and transmission electron microscopy (TEM). TEM images of samples show that the size of SnO₂ : Sb nanoparticles is in the range 4–5 nm. The absorption and luminescence properties of samples were investigated at room temperature. The band gap of SnO₂ : Sb varied from 3.9 to 4.2 eV with variation of the Sb dopant concentration. The nature of the photoluminescence peaks of the SnO₂ : Sb nanoparticles will be discussed.