Mn-Cu mixed oxides were prepared by co-precipitation varying the aging time for 4, 18 and 24 h. The catalytic performance in propane and ethanol total oxidation on these samples was better than on Mn2O3 and CuO pure oxides. The increase of the aging time enhanced the activity and the selectivity to CO2. The nature and disposition of the phases forming the catalytic system as well as the effect of the precipitated aging time was determined by means of specific surface area measurements, X-ray diffractometry (XRD), infrared spectroscopy (FTAR), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (TPR) and temperature programmed desorption of oxygen (O-2-TPD). The catalytic behaviour seems related to the existence of a Cu1.5Mn1.5O4 mixed phase and the easier reducibility of the catalysts. (c) 2006 Elsevier B.V. All rights reserved.