Ten mesio-occlusodistal composite resin inlays were fabricat by the indirect method and cemented in extracted posterior teeth. The restorations were subjected to thermocycling and subsequently placed in a 50% silver nitrate solution. Specimens were prepared and inspected under a stereoscopic mic roscope and a scanning electron microscope. The results showed a total absence of microleakage at the margins terminating in enamel and a slight degree of microleakage in only two margins terminating in cementum. This corresponded with the general absence of defects and gaps that was observed in the scanning electron microscope. The exception was in the two specimens that exhibited dye penetration; these were found to have material in the marginal areas.