The behavior of Pd-Au alloys, prepared by electrochemical codeposition, has been studied in acidic solutions (1 M H2SO4) using mainly the cyclic voltammetry technique. Morphology of the alloy surface and bulk compositions were examined by SEM/EDAX method. Various types of voltametric behavior during potential cycling in the oxygen region are presented. The influence of hydrogen absorption on electrochemical properties of surface oxides is demonstrated. The problem of the nature of oxygen electrochemisorbed on Pd-Au alloys is discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.