Background: The influence of recently marketed fluoridated mouth rinses on the surface roughness of the newly nano-filled composite resins has not yet been adequately investigated. Objectives: This study aiming at evaluating the effects of different types of mouthwashes on surface roughness of different types of composite resins. Materials and Methods: This experimental in vitro study included 3 types of mouthwashes (Colgate Plax, Listerine, and Aloe Dent) and 3 types of composite resins (Z350, Z250, and Art). Six specimens were prepared for each material in each group. All specimens were fabricated at room temperature 23°C. Pre-test measurements were recorded for all specimens in the three test groups using the profilometer after storing all specimens in distilled water for 24 hours. Post- test measurements were recorded after storing each specimen for 1 minute/day for 1 week. Means and standard deviations were calculated and the differences in means (before and after) between the tested groups were performed using Paired Sample t-test with p value <0.05 as a significant level. Results: The pre-test means and SDs for the tested groups according to the type of mouthwash were 140.7±53.86 for group B, 159.63±44.34 for group C, and 166.55±51.16 for group D. The after-test readings were 158.42±47.63, 176.11±49.30, and 171.49±31.81 for the same group, respectively. The highest difference in means between before and after measurements was found in group B with a value of 17.73±10.82 with high significant level (P <0.001). The difference in means for group C was 16.48±8.42 which was also highly statistically significant (P <0.001). The lowest difference, however, was found between the means in group D with a value of 4.94±48.22 with no significant level (P >0.05). Conclusion: Among the tested storage mouth rinses, Aloe Dent was found to have the least effect on surface roughness.