Background: To study the effect of different surface treatments of MTA on bond strength of composite resin to MTA. Materials & methods: A total of 20 cylindrical acrylic blocks, each containing a hole, were prepared and filled with ProRoot MTA. The blocks were divided into four groups for further analysis: Group 1, which received no surface treatment; Group 2, where phosphoric acid etching was performed. The results were analysed using SPSS software. Results: The Kruskal-Wallis test revealed a statistically significant difference in microshear bond strength values among the four study groups (P < 0.05). Among these groups, Group 4, which underwent HF etching and silane application, exhibited the highest microshear bond strength (28.0), while Group 3, treated with sandblasting, demonstrated the lowest value (4.8). Conclusion: The preferred methods for surface treatment of MTA before bonding with composite resin were found to be phosphoric acid etching or HF etching combined with silanization.