A paper by Yu and Jin (Surf. Interface Anal. 2001; 31: 338) describing Auger microanalysis of ceramic insulating materials is commented upon. The major criticism regards the authors' claim that reliable scanning Auger microscopy (SAM) analysis can be performed on the (Y,La)-doped alpha -Si3N4 sample when this is made thinner by dimpling and Ar+ ion etching, two procedures that prevent surface charging phenomena. In fact, this comment shows that: Ar+ ion bombardment produces insurgence of Si-Si bonding states as a result of chemical reduction of surface SixNyOz species, so that no chemical-state information actually can be derived from the Si LVV and Si KLL spectra of this sample because the layers probed by Auger analysis are not very reminiscent of the genuine chemical composition of this material; and SAM imaging results obtained from the same material are heavily affected by topographical artefacts and no reliable information thus can be derived from its true microchemical surface lateral heterogeneity. It is suggested that the use of reflected electron energy-loss microscopy, i.e. a technique that is in itself immune to surface charging phenomena, would have been likely to assist better than SAM in the microchemical characterization of insulating materials. Copyright (C) 2001 John Wiley & Sons, Ltd.