In this work, a new technique for analyzing interfacial conditions in completed adhesive bonds is discussed. This method is based on the sensitivity of Stoneley waves, which propagate along the boundary between dissimilar solid media, to changes in the material properties of the interface region. Stoneley wave attenuation measured after processing was found to increase as a function of increasing surface roughness in specimens of borosilicate crown glass bonded with an aerobic cement to a substrate of 7740 Pyrex mirrorglass. Possible extensions of these results to high_strength structural adhesively bonded composites are discussed.