Objectives: The purpose of the present study was to evaluate microtensile bond strength of a microhybrid resin composite restorative materials which is used with an etch-and-rinse adhesive on enamel and dentin after treatment with Er,Cr:YSGG laser with different output power and pulse frequency combinations. Methods: Enamel (E) and dentin (D) samples were prepared from bovine incisors. Following immersion of teeth in the acrylic blocks and flattening surfaces, samples were divided into 8 subgroups as follows (n=5): E-Control (no treatments), E-Bur (mechanical roughening was performed using high-speed diamond bur), E-Laser 6W-20Hz, E-Laser 6W-35Hz, E-Laser 6W-50Hz, E-Laser 3W-20Hz, E-Laser 3W-35Hz, E-Laser 3W-50Hz; D-Control (no treatments), D-Bur (mechanical roughening was performed using high-speed diamond bur), D-Laser 3W-20Hz, D-Laser 3W-35Hz, D-Laser 6W-50Hz, D-Laser 1.5W-20Hz, D-Laser 1.5W-35Hz, D-laser 1.5W-50Hz. Following acid-etching all surfaces, composite build-ups were done. Samples were cut into resin-enamel/dentin sticks with dimensions of 0.8 mm². Four sticks were randomly selected from each tooth (n=20) to be tested in microtensile bond strength tests. Results: E-Laser 3W-50Hz (36.22±6.0 MPa) showed significantly highest bond strength with the exception of E-Control (32.85±9.8 MPa). For dentin, E-Control (27.70 ± 7.0) and E-Bur (24.98 ± 8.8) showed significantly different bond strength from other groups. Conclusions: Laser irradiation could enhance or impair the microtensile bond strength depending on the tooth structure and laser parameters used. Keywords: Er, Cr:YSGG laser, dentin, enamel, bond strength, laser parameters