We show that the commonly accepted measurement of the critical potential for alloy dissolution calculated based on extrapolation of anodic polarization data results in an overestimation of this quantity. A series of constant applied potential experiments prove to be a more accurate method for critical potential determination. For the system Ag0.7Au0.3 in 0.1 M HClO4, we find that the true critical potential lies between 0.990-1.020 V vs. normal hydrogen electrode. This is approximately 115 mV below that conventionally determined by anodic polarization data. (C) 2003 The Electrochemical Society.