Aim: This study evaluated the effects of the ultrasonic scaling on the surface roughness of the restorative materials at different power settings. Materials and Methods: 48 specimens of rectangular recesses (12x8x1.5mm) of Teflon molds were made, filled with a nanohybrid composite resin and cured. Pre-ultrasonic surface roughness was measured using Surface Roughness Tester. The specimens were divided randomly into 2 groups with each group consisting of 24 specimens. The group 1 and group2 specimens were subjected under medium and high power setting ultrasonic scaling respectively. Post-ultrasonic surface roughness was measured as mentioned previously. Data were analysed with paired t-test and independent t-test. Results: Statistical analysis was done using SPSS software version 16.0. P <0.05 was considered statistically significant. The results showed that surface roughness of the restorative material increased after ultrasonic instrumentation. Intergroup comparison revealed that post-ultrasonic surface roughness was more in the high power setting when compared to the medium power setting. Conclusion: It is recommended to use medium power setting ultrasonic scaling and to repolish the restorations to bring down the surface roughness to the clinically acceptable level.