The reactions of HCOOH and CH3COOH on CeO2(111) and CeO2(100) were studied using temperature programmed desorption (TPD) and high resolution electron energy loss spectroscopy (HREELS). The carboxylic acids were found to dissociate on both surfaces to form carboxylates. Adsorbed formates and acetates decomposed near 600 K to produce primarily the dehydration products CO and CH2CO, respectively. This result is consistent with previous studies which have indicated that the ease of reduction of the oxide is the primary factor in determining the selectivity for dehydration versus dehydrogenation during carboxylate decomposition. In addition to CO and CO2, small amounts of formaldehyde were produced during formate decomposition on both CeO2(111) and CeO2(100). In contrast, acetone was observed as a product during acetate decomposition only on the CeO2(111) surface.