Doping of W into VO2 was done by high-energy (1.0 MeV) ion beam implantation and thermal annealing for the first time. The implantation was performed with different ion doses of 0.86, 2.18 and 6.12 x 10(15) ions/cm(2) on a VO2 polycrystalline film sputter-deposited on Si. The film was characterized by Rutherford backscattering spectroscopy, atomic force microscopy and spectrophotometry. Deterioration of thermochromism and change in surface morphology after implantation, resulting from the irradiation damage such as amorphization, were observed and the extent increased with ion dose. Recrystallization of the implanted film and recovery of thermochromism were obtained by annealing at 400 degrees C in air for 60 min. The W doping resulted in a substantial reduction in the critical temperature tau(c) for the phase transition of VO2.