Rubber/metal composites are known to be highly durable in a normal atmospheric condition. However, when they are exposed to an aggressive environment such as the marine environment, they tend to fail prematurely. The failure is usually caused by the loss of adhesion of the rubber to metal substrate. The aim of this work is to elucidate the adhesion failure mechanism by using a commercial bonding system for bonded rubber/metal exposed in a marine environment. A simulation study that was carried out through a salt spray test indicated that corrosion of the exposed metal substrates induced the loss of adhesion through cathodic disbonding. Laboratory exposure in alkaline medium, cathodic disbonding, and anodic undermining tests suggested that the hydroxyl ions generated from corrosion reactions contributed to the adhesion failure.