OBJECTIVE This study compared microleakage of three adhesives in class V (CI V) composite restorations prepared with Er,Cr:YSGG laser. BACKGROUND Changes produced on enamel and dentin surfaces subsequent to laser irradiation influence microleakage of composite restorations. METHODS CI V cavities were prepared in 80 sound extracted human premolars with Er,Cr:YSGG laser. The teeth were randomly divided into 4 groups (n = 20). In group 1, a total-etch adhesive was used, and two-step and one-step self-etch adhesives were used in groups 2 and 3, respectively. Group 4 was the control group with no adhesives. Following restoration and thermocycling, microleakage was evaluated. To compare microleakage in occlusal and gingival margins in each group, the Wilcoxon test was used. Kruskal-Wallis analysis was used for comparison of occlusal and gingival microleakage, and two-by-two comparisons were made using the Mann-Whitney U test. RESULTS There were significant differences in microleakage between occlusal and gingival margins in each group except for the control group. Significant differences were observed in occlusal and gingival microleakage among all the groups. Two-by-two comparisons revealed significant differences in occlusal microleakage between the control group and the other groups. There were significant differences in gingival microleakage between groups 1 and 2 and groups 1 and 3; however, differences in gingival microleakage between groups 2 and 3 were not significant. CONCLUSIONS With all the adhesives, microleakage was significantly higher in gingival margins compared with occlusal margins. In occlusal margins, there were no significant differences in microleakage among the three adhesives. In gingival margins, self-etch adhesives revealed less microleakage than the total-etch adhesive.