The deleterious effects of water on the physico-chemical aspects of the durability of adhesively bonded aluminium joints has been investigated. Emphasis was placed on analytical techniques that lead to the better understanding of changes induced at the metal/epoxy interface by the presence of water. Analytical techniques such as contact angle measurements, X-ray photoelectron spectroscopy and X-ray diffraction were practical in obtaining information on the chemical composition and structure of the samples. Chemical conversion-coated samples were found to be much more stable in wet conditions compared to samples without conversion coating. The surface structure on the adherend, after extensive immersion times, was found to consist of a compact layer of bayerite with traces of gibbsite. The calculations of interfacial energy, gamma(sl), and work of adhesion in dry and wet conditions, W(A) and W(Al), were carried out to evaluate the maximum bond strength. It was found that the durability of the bond in the presence of water was quite high for the XD4300/6061-T6 joint systems.