This in vitro study investigated the effect of Scotchbond Dual Cure bonding agent on microleakage of sealant bonded to saliva-contaminated enamel. To determine microleakage, sealants were placed on previously extracted premolars, with or without bonding agent, in the presence or absence of salivary contamination. The curvilinear extent of microleakage was measured on the mesial and distal aspects of the sealant-enamel interface with a digital-image analyzer. The results revealed a statistically significant difference between the microleakage of the contamination/sealant group and the other three groups. The Scotchbond/sealant group exhibited slightly less leakage than did the sealant only and contamination/Scotchbond/sealant groups. Scanning electron microscopy was used to examine the enamel-material interface. Placement of Scotchbond between the sealant and enamel reduced microleakage of sealants applied under conditions of salivary contamination.