Background: To investigate how various surface treatments of MTA influence the bond strength between MTA and composite resin. Materials & Methods: A set of 20 acrylic blocks with cylindrical shapes, each featuring a hole, were prepared and filled with ProRoot MTA. These blocks were then categorized into four groups for subsequent examination: Group 1, which underwent no surface treatment; Group 2, subjected to phosphoric acid etching; Group 3, treated with sandblasting; and Group 4, exposed to hydrofluoric acid (HF) etching, followed by rinsing and silane application. Results: Significant differences in bond strength values were observed between Group 1 and Groups 3 and 4. Additionally, there were noteworthy variations in bond strength values between Group 2 and Group 3, as well as between Group 3 and Group 4. Conclusion: Optimal approaches for preparing the surface of MTA before composite resin bonding were determined to be either phosphoric acid etching or HF etching in conjunction with silanization. Keywords: mineral trioxide, composite, bond strength.