MoS 2 can generate useful molybdenum oxides by thermally reacting with LiF or Ag nanoparticles (NPs). MoS 2 easily loses sulfide and reacts with oxygen gas upon heating in air to give orthorhombic molybdenum trioxide, α-MoO 3. Morphological changes of α-MoO 3 from 500 to 900 C were investigated using X-ray powder diffraction and scanning electron microscope. The strong diffraction peaks of the (020), (040), and (060) planes at 800 C revealed highly anisotropic growth of the oxides with a layered crystal structure. In the presence of LiF, MoS 2 reacts with oxygen gas to generate Li 2 MoO 4 and MoO 2 , depending on the LiF concentration. In the presence of Ag NPs, the thermal reactions of MoS 2 at 800 and 900 C give silver molybdates Ag 2 Mo 2 O 7 and Ag 2 MoO 4 , respectively. These results demonstrate that MoS 2 is an important precursor for generating useful molybdenum oxides on the surface of inert substrates without requiring sophisticated, expensive equipment.