This paper reports on an investigation of the performance of an organofunctional silane (gamma-aminopropyltrietoxysilane) as an adhesion promoter in the bonding of stainless steel with an epoxy-based adhesive. Joint strength of adhesive/silane/metal systems is assessed using a three point flexure test. Aspects considered were the influence of the concentration of the silane solutions, pH and aging time of these solutions and the nature of pre-treatment process (in sulfo-chromic media) of the metallic substrates. The effectiveness of such a coupling agent was discussed with respect to analytical data obtained by low-energy electron induced X-ray spectrometry (LEEIXS) which permits to characterize the silane film that is chemically adsorbed and polymerized onto the metallic substrate. influence of the addition of phenyltrietoxysilane in the gamma-aminopropyltrietoxysilane solution is also shown.