Objective: The purpose of study was to compare the surface roughness of 5 resin composites after polished with Sof-Lex polishing system. Materials used in this study were Clearfil ST, Filtek Supreme, Esthet-X, Z100 and Clearfil AP-X. Methods: Ten specimens of each resin composites (total 50 specimens) were studied. The cylindrical specimens in 5mm diameter were prepared and fixed in PVC rings by self-cured acrylic resin. All specimens were polished with Sof-Lex polishing system. Then, all specimens were evaluated for surface roughness using profilometer. The mean surface roughness values were analyzed by using 1-way ANOVA at 95% confidence interval. Results: The mean surface roughness values of Clearfil ST, Filtek Supreme, Esthet-X, Z100 and Clearfil AP-X were 0.065 micron (95% CI: 0.055 to 0.076), 0.072micron (95% CI: 0.064 to 0.081), 0.085 micron (95% CI: 0.079 to 0.090), 0.116 micron (95% CI: 0.104 to 0.128) and 0.158 micron (95% CI: 0.133 to 0.183), respectively. Post hoc comparisons using Bonferroni showed no significant differences among 5 composites (p<0.05) but Filtek Supreme had no significant difference from Clearfil ST (p=1.00), and Esthet-X had no significant difference from Filtek Supreme (p=0.454). Conclusion: Base on this study, after polished with Sof-Lex, Clearfil ST presented the smoothest surface, followed by Filtek Supreme, Esthet-X, Z100 and Clearfil AP-X.