A comprehensive study of the surface basicity and acidity of alkaline earth metal oxides, La 2 O 3 /CaO, CeO 2 /CaO and ZnO-doped NaOH (11 mol-%)/CaO which had earlier been tested as catalysts for the oxidative coupling of methane was performed. For determining the acid-base properties two probe reactions, i.e., the decomposition of 2-propanol to acetone and propene and the retroaldolisation of diacetone alcohol, further the temperature-programmed desorption (TPD) of CO 2 , the benzoic acid titration with Hammett indicators and DRIFT spectroscopic investigations of the adsorption of CO 2 and pyridine were applied. Using alkaline earth metal oxides as references the applicability of the different characterization methods was evaluated. The decomposition of 2-propanol was found to be of restrictive applicability for determining the basicity of a metal oxide. A comparison of the different catalyst systems revealed that La 2 O 3 /CaO and CeO 2 /CaO catalysts showed highest surface acidities, while highest base strength and highest amount of strong basic surface sites were observed for Zn 2+ /NaOH (11 mol-%)/CaO catalysts and SrO.