The acoustic emission (AE) response of an implant quality 316L stainless steel (SS) during slow strain rate tensile testing (SSRT) at a constant strain rate of 7.35 x 10(-6) has been measured in Hank's solution with pH 4 at and around the pitting potential, E-pit, of 110 mV(SCE), AE signals were detected by using a piezoelectric sensor. AE Signals recorded in the homogeneous plastic region of the stress-strain curve at potentials greater than E-pit were found to increase in activity and amplitude with increasing anodic potentials beyond pitting. Occurrence of this increase in AE signals took place at progressively decreasing levels of plastic strain as the potential increased beyond pitting. Localization of plastic deformation was suggested to explain the attenuation of the AE signals beyond necking. (C) 1999 Elsevier Science Ltd. All rights reserved.