SnO2 quantum dots (QDs) were controllably synthesized by laser ablation in liquid (LAL). The HRTEM image shows that the diameters of the SnO2 nanoparticles fall into a small range of 1-5 nm, with the majority being less than the exciton Bohr radius of SnO2 (similar to 2.7 nm). The Selected Area Electron Diffraction (SAED) pattern of SnO2 QDs shows tetragonal crystalline structure. The photoluminescence (PL) spectrum of such SnO2 QDs exhibits blue and green emission peaks at 445 nm and 540 nm respectively. These QDs have potential future applications in optoelectronics, biosensor and other modern technologies. (C) 2012 Elsevier B. V. All rights reserved.