Thin films of mixed metal oxides were deposited on glass by metal-organic chemical vapour deposition (MOCVD) and plasma enhanced chemical vapour deposition (PECVD). A controlled mixture of precursor gases, tungsten and molybdenum carbonyls, was used to deposit tungsten and molybdenum oxides simultaneously. Deposition rates in PECVD reached 0.5 mu m min(-1), which is very fast compared with the 0.6 mu m h(-1) rate obtained in MOCVD. The mole ratio of W to Mo in the deposit was found to be identical to that in the precursor mixture within a range of experimental error. X-ray diffraction did not detect crystallinity in the MOCVD films, whereas the crystallinity of PECVD films increased with substrate temperature in the range 200-300 degrees C. The crystalline products were identified as ternary phases, indicating codeposition or reaction between the two oxides.