Five current dentin adhesives were evaluated for their ability to bond to caries affected dentin. The materials were a total etch (Solid Bond (SB)), two self etch (Clearfil SE Bond (CSE), Etch and Prime (EP)), two one bottle (Prime and Bond 2.1 (PB), One Coat Bond (OCB)). 60 extracted molar teeth with proximal caries (mesial or distal) extending into mid-dentin were used. By grinding normal and caries-affected proximal surfaces, flat dentin surfaces were obtained. The surfaces were then bonded with each adhesive systems and composite resins were added to the surfaces by packing the material into a cylindrical-shaped plastic matrix with an internal diameter of 2.5 mm and height of 3 mm. Shear bond testing was performed following 10 days incubation of specimens in distilled water at 37 °C. Results were analyzed by Kruskal-Wallis ANOVA, and Mann-Whitney U multiple comparison test and Wilcoxon Rank Tests.The results obtained with CSE, SB, and EP were similar in caries affected and normal dentin (p>0.05). But bonds made to normal dentin with OCB and PB were lover (p Keywords: Caries affected dentin, bond strength, dentin bonding agent