The relationship between the adhesive bonding strengths and the bonding areas (sizes) is important for material and structural designs, because adhesive bonding is widely used not only in small scale electronic devices, but also in large-scale composite-metal joints of modern aircraft/ship structures. Therefore, a systematic experimental investigation on adhesive bonding strengths of polymer/polymer, metal/metal, and polymer/metal joints was conducted. Results show that the size effect of the bonding strengths is small for the current bonding areas (from 30 to 300mm(2)), which are widely employed in most of the test standards for engineering designs.