Owing to its outstanding characteristics in good affinity to heterogeneous materials, corrosion resistance and on-the-spot processing capability, epoxy has been widely used as adhesives in retrofitting structures with carbon fibre reinforced polymer (CFRP). In this study, different weight fractions of multi-walled carbon nanotubes (MWCNTs) will be dispersed into epoxy to produce toughened adhesives that can improve the CFRP/structure bonding performance. The preliminary results indicate that adding 2% MWCNTs to Araldite-420 increase its ultimate strength by 17% and its elastic modulus by 14%. Ultrasonic mixing may increase Sikadur-30’s elastic modulus but reduce its strength and ductility regardless of the MWCNTs concentration. The mechanism of MWCNTs infusion effects on the mechanical properties of epoxy is also examined using SEM.