Gold catalysts (similar to 1%) supported on CeO2, on CeO2 modified by inclusion of lanthanum (10%) or iron (5%), and on CeZrO4, have been prepared, characterised (N-2 physisorption, XRD) and tested for CO oxidation (200-300 K): stability tests for up to 75 h (Salford) and 24 h (Delft) have also been conducted. All three 'modified' catalysts show 10-20% conversion at similar to 200-243 K, but lanthanum and zirconium modifiers lead to slightly decreased activity at 243-293 K.Au/La-CeO2 and Au/Fe-CeO2 in particular, however, show exceptional stability in life-tests at ambient temperature. DRIFTS results on fresh and used catalysts suggest that this may be due to both better retention of surface hydroxide groups and lesser formation of carbonate/bicarbonate ions near gold particles during reaction. Mechanisms to account for this behaviour are considered and hydroxyl groups acting catalytically may be responsible for stable activity. (C) 2008 Elsevier B.V. All rights reserved.