For correct quantitative interpretation of Auger spectra of group III-nitrides and their alloys it is necessary to have the relative sensitivity factors of elements and the sputtering yields measured for the material under analysis. These data are not available in the literature for those materials. In this work, the quantities have been determined experimentally that are needed for reliable and precise quantitative interpretation of Auger spectra of such materials, thus of AlN, GaN and their ternary alloys Al