OBJECTIVE: The aim of this study was to evaluate the effect of two different cavity disinfection procedures (chlorhexidine gluconate-based cavity disinfectant and Er,Cr:YSGG laser irradiation) on the bond strength of two different types of adhesive systems (Adper Single Bond 2 [SB] and Clearfil SE Bond [SE]). MATERIALS AND METHODS: Thirty human third molars were ground flat to expose midcoronal dentin. After the dentin surfaces were polished with 600-grit silicon carbide paper, the teeth were randomly assigned to six groups (n = 5) according to the cavity disinfection procedure and the adhesive resin: Group I, etch and rinse adhesive (SB); Group II, self-etch adhesive (SE); Group III, cavity disinfectant application (cavity cleanser) + SB; Group IV, cavity disinfectant application + SE; Group V, laser irradiation (Er,Cr:YSGG laser, 20 Hz; 0.75 W; 15% water, 15% air) + SB; Group VI, laser irradiation + SE. For each group, the composite crown was incrementally fabricated with a composite resin. Following storage in distilled water at 37 degrees C for 24 h, the bonded specimens were serially sectioned into rectangular beams (n = 32). Bond strengths were determined using a microtensile tester at a crosshead speed of 0.5 mm/min. Data were analyzed using two-way ANOVA, and multiple comparisons were performed using post hoc Duncan's test (p < 0.05). RESULTS: Cavity disinfectant application and laser irradiation produced significantly higher bond strength values compared to the control group for SB. For SE, only laser irradiation improved the bond strength values compared to the control. There was a statistically significant decrease in the bond strength values of the specimens that were subjected to cavity disinfectant before SE application. The failure mode was mainly adhesive in all groups. CONCLUSION: Cavity disinfectant application and laser irradiation may influence bond strength, depending on the adhesive system used. As a cavity-disinfecting procedure, laser irradiation might enhance the bond strength of etch and rinse and self-etch adhesive systems.