The NARP-(Nitric-Oxide Ammonia Rectangular-Pulse) technique is often used as a method for the quantitative determination of the number of terminal Me=O oxygen species in metal oxide catalysts. The amount of nitrogen formed when pulsing NO/NH3-mixtures over the catalysts are related to the surface density of Me=O groups. In the present paper the applicability of this method, which is not generally accepted in literature, was tested for unsupported and supported vanadia- and molybdena catalysts. The influence of the reaction temperature and calcination temperature of the catalysts applied on the nitrogen formation do not support the applicability of this method for a quantitative determination of the number of terminal Me=O oxygen species on metal oxide surfaces. However, the comparison of NARP results and XPS surface analyses presume, that the NARP technique can be used to determine the surface coverage of VOx and MoOx species on supported V-(Mo-)catalysts.