Objective: To evaluate the effect of MDBP-containing self-etch (SE) adhesive and different dentin surface pretreatments on antibacterial activity Materials and Methods: A total of forty disc shaped specimens fabricated (8 mm in diameter and 1.5 mm thickness)  were divided into four main groups according to type of the surface treatment method; deionized water(control), CHX,  Papin enzyme and Riboflavin. Each group was sub-divided into 2subgroups (n=5) according to the type of adhesive: classic or MDPB containing SE adhesives. Bonded specimens were stored in deionized water for 24 hr. (n=6). The plates contained dices shaped specimen was incubated at 37^o C for 24. The diameter of inhibition zones were measured with sliding callipers and the data were statistically analyzed using Mann-Whitney U-test and multiple comparison Kruskal Wallis H-test and level of significance were tested. Result: The diameter of inhibition zones evaluated that Clearfil SE protect has antibacterial activity and pre-surface treatment with CHX and Papin enzyme increased antibactrial activity with both types of adhesives.Conclusions: MDPB containing SE adhesives have antibacterial activity. Application of CHX prior to adhesive application improves antibacterial activity compared to Papin and Riboflavin.