Purpose: Occlusal adjustment of ceramic restorations may be necessary to correct interferences. A rough surface may abrade opposing tooth or restorative materials, thereby increasing plaque accumulation. The aim of this study was to compare the effect of four finishing systems and diamond paste on ceramic roughness. Materials and Methods: Forty ceramic disks were distributed into four randomized groups. The initial roughness of all samples was increased with a diamond bur. Samples in group 1 were finished with white silicon and black rubber; group 2 samples were finished with Shofu rubbers; group 3 samples were finished with diamond burs; and group 4 samples were finished with Sof-Lex disks. All samples were then polished by Yeti diamond paste. The surfaces were characterized by means of a surface roughness analyzer. The parameters Ra, Rpm, and Rz were determined. Four roughness recordings were made before and after diamond bur finishing, and before and after Yeti paste polishing. ANOVA was used to test the significance of differences between groups at each stage of the procedures. Results: All four methods reduced the average roughness of the samples. The most effective system was Sof-Lex disks. Diamond paste can round the profile shape and reduce the height of maximum peaks of the surface, but it may not improve the average roughness. Conclusion: All systems tested reduced the roughness of ceramic samples, but the Sof-Lex disk finishing system may be more efficient than other methods. The efficiency of the diamond paste is not clear. Int J Prosthodont 2003;16:74–77.