A TiO2 surface was readily modified with nanosized gold particles prepared by the thermal relaxation technique. Adsorption of the gold particles was very rapid, and the adsorbed gold particles distributed independently. By the two-step calcination of the modified TiO2, the nanosized gold particles were immobilized on the TiO2 surface without size growth or coagulation. The supported gold particles showed low-temperature catalytic activity on CO oxidation. The preprepared nanosized gold particles interacted with TiO2. Copyright 1999 Academic Press.