Mating parts often experience repetitive relative motion termed fretting which results in friction, wear, as well as acoustic emission signals. Acoustic emission signals have the potential for monitoring the condition of the surfaces participating in the frictional process. In structural health monitoring studies, where the focus is on quantifying crack growth related acoustic emission signals, the signals generated by other mechanisms give rise to undesirable false positives. A major source of such false positives are fretting related signals. The present paper describes an experimental approach for characterizing the friction related acoustic emission signals. A test fixture is developed to obtain fretting related signals under controlled conditions. The waveforms are analyzed to extract features common to these signals. A comparison of acoustic emission signals related to fretting and crack growth is provided.© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.