Objective: The aim of this study was to evaluate the tensile bond strength with different adhesives system on primary dentin teeth treated by Er:YAG laser or high speed drill. Materials and Methods: the bucal face of 38 primary canine teeth was ground using grit silicon carbide paper (#120,400,600) and treated by different adhesive system: G1: High Speed Drill (HSD) + 35% Phosphoric Acid (PA) + Single Bond (SB) + Composite Resin (CR); G2: HSD + Self-Etching Adhesive One Up Bond F (OUB) + CR; G3: Er:YAG laser (4Hz, 80mJ, 25,72J/cm2 )(L) + PA + SB + CR; G4: L + SB + CR; G5: L + OUB + CR. Results: the averages (Mpa) were: G1- 3,18 (±1,24); G2- 1,79 (±0,73); G3- 3,17 (±0,44); G4- 8,29 (±1,86); G5- 7,11 (±2,07). The statistics analysis (ANOVA and Turkey) showed that laser + PA+SB,SB or OUB raised the adhesion in comparison with HSD+PA+SB and HSD+OUB (p=0.000). Conclusion: the laser irradiation with Er:YAG caused significative raise on union adhesion between differents adhesive system on primary teeth dentin.