Purpose: To evaluate microleakage from an antibacterial adhesive and bonding agent added to the ssure sealant on intact enamel. Materials and Methods: One hundred twenty sound third mandibular molars were randomly divided into 6 groups of 20 teeth each. Occlusal pits and ssures were sealed with un lled sealant material (Clinpro, 3M) after pretreatment with 1. phosphoric acid etching (control); 2. acid etching + Adper Single Bond 2 (SB, 3M); 3. chlorhexidine digluconate (CHX, Ultradent) + acid etching; 4. CHX + acid etching + SB; 5. acid etching + Clear l Protect Bond (CPB, Kuraray) 6. CPB alone. After 6-month water storage and thermocycling, the specimens were placed in 0.5% fuschin, sectioned and evaluated under a digital microscope. The data were compared between groups with Kruskal-Wallis and Mann-Whitney tests. Results: Differences between groups were statistically signi cant at P 0.05. Acid etching alone and with SB showed the lowest microleakage, followed by acid etching + CPB. Chlorhexidine with and without bonding agent showed the greatest microleakage. Conclusion: Conventional acid etching alone or with a one-bottle adhesive were the two most effective methods of reducing microleakage from ssures. Acid etching together with a self-etching adhesive showed better results than self-etching alone. Appling CHX increased microleakage in sealed teeth. Keywords: antibacterial agents, dental adhesive, dental leakage, pit and ssure sealants