Effect of upper and lower potential limits on Pt stability in potential cycling experiments is studied for 20 wt. % Pt/C E-TEK catalyst in acidic medium. The Pt electrochemical surface area (ECSA) loss is observed as a parameter to study different potential ranges. It is observed that at upper potential limits the ECSA loss is influenced by electrochemical Pt dissolution while at lower potential limits reduction of b Pt oxide phase plays important role in ECSA loss.