Purpose: To evaluate whether the application of an enamel etchant (Etch-37 BAC) and a desensitizer (PrepEze desensitizer) which contain the antibacterial agent benzalkonium chloride (BAC) affects the bond strength of the orthodontic resin Transbond XT. Materials and Methods: Eighty-five extracted premolars were used. They were divided into four groups: 1. Transbond XT, 2. Etch-37 BAC/Transbond XT, 3. PrepEze/Transbond XT, 4. Etch-37 BAC/PrepEze/Transbond XT. Shear bond strength was measured using a universal testing machine with a crosshead speed of 1 mm/min. The adhesive remnant on the tooth after debonding was quantified using image analysis equipment. Results: No significant differences were found in shear bond strength when Transbond XT was bonded with the conventional etchant or with Etch-37 BAC (p > 0.008). PrepEze decreased the shear bond strength and the amount of adhesive remnant on the tooth after debonding significantly (p 0.008). The amount of adhesive remnant on the tooth surface diminished significantly when the enamel was etched with Etch-37 BAC (p 0.008). Conclusions: The bond strength values obtained with the application of Etch-37 BAC are similar to those obtained with a conventional etchant. However, the application of PrepEze significantly decreased the bond strength of Transbond XT. Keywords: antibacterial bonding systems, shear bond strength, bracket bonding