The anodic dissolution of copper has been examined in deaerated 0. 1 M HCl aqueous solution in the presence of H//2O//2. Concentrations of H//2O//2 up to 0. 2 M were studied at a rotating copper disk-platinum ring electrode. The open circuit potential (OCP) of copper was found to depend on both peroxide concentration and rotation rate. The OCP shifts towards more positive values with increasing H//2O//2 concentration (C) and decreasing rotation rate ( OMEGA ). The dependence of OCP on (C/ OMEGA ** one-half ) was the same as for oxygenated solutions reported earlier, at small values of (C/ OMEGA ** one-half ). At higher values of (C/ OMEGA ** one-half ), departure from the expected behavior was observed. The current-voltage curves for anodic dissolution of copper were also influenced by the presence of peroxide. The curves recorded with the potential scanned in the positive direction showed the expected 60 mV slope, but the reverse scans showed significant departures. At a given potential scan rate, hysteresis was observed which was larger for higher H//2O//2 concentrations, lower rotation rates, and more positive anodic potential limits. Monitoring the cuprous ions at the outer Pt ring revealed that there was a complex set of events taking place at the copper surface, including film formation and the appearance of cupric ions.