A comprehensive study of the surface basicity and acidity of alkaline earth metal oxides, La2O3/CaO, CeO2/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 CO2, the benzoic acid titration with Hammett indicators and DRIFT spectroscopic investigations of the adsorption of CO2 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 La2O3/CaO and CeO2/CaO catalysts showed highest surface acidities, while highest base strength and highest amount of strong basic surface sites were observed for Zn2+/NaOH (11 mol-%)/CaO catalysts and SrO.