The current study evaluated the influence of KTP (Potassium-Titanyl-Phosphate) laser irradiation, 2% chlorhexidine gluconate and Clearfil Protect Bond on the microleakage of Class V composite restorations. Thirty human premolars were selected for cavity pretreatment. After Class V cavity restorations on the buccal and lingual surfaces, the teeth were randomly divided into four groups: Group I-Clearfil SE Bond; Group II-KTP laser + Clearfil SE Bond; Group III-2% chlorhexidine gluconate + Clearfil SE Bond; Group IV-Clearfil Protect Bond. The cavities were restored with resin composite. The teeth were then thermocycled for 500 cycles, dried and sealed with nail varnish, leaving 1 mm around the restorations and immersed in 0.5% basic fuchsin for 24 hours. They were then rinsed, dried and sectioned, and microleakage was assessed by dye penetration at the occlusal and gingival surface of the teeth using a stereomicroscope (30x). There were no significant differences among the four groups at the gingival surface (p > 0.05). Microleakage at the occlusal margins of all the groups was compared; differences between the KTP laser and chlorhexidine gluconate group and the KTP laser and Clearfil Protect Bond group were found to be statistically significant (p < 0.05).