The reactivity of Co-Mg-O in the gas phase selective oxidation of methanol, ethanol, 1-propanol, and 2-propanol was studied by using a tubular flow reactor. The Co-Mg-O system has shown its potential as a selective oxidation catalyst for the production of aldehydes from ethanol and 1-propanol. The major selective oxidation products for the oxidation of ethanol and 1-propanol were ethanal and propanal, respectively. In the operating conditions investigated, ethanal and propanal yields up to 58% and 53%, respectively, were obtained. Oxidation of methanol produced mainly CO2 while the major product for the oxidation of 2-propanol was propene. Finally, two reaction pathways were proposed.