Uniform single-crystalline tungsten oxide (WO3) nanosheets have been synthesized in a large-scale with W powders as starting material. The results from the thermal stability measurements show that the as-synthesized WO3 nanosheets are anhydrous. Their thickness and length are similar to 80 and similar to 500 nm, respectively. They exhibit blue luminescence emissions at similar to 431, 486 and 497 nm, UV emissions at similar to 362 and 398 nm. The blue emissions are resulted from the band-band indirect transition and the UV emissions should be attributed to the defect states of WO3. The growth mechanism of the two-dimensional WO3 nanosheets is discussed. (C) 2008 Elsevier Ltd All rights reserved.