Introduction: Acid etching causes a selective demineralization that increases the free surface energy, enamel porosity, and increase in surface area. In order to decrease marginal microleakage, alternative enamel pre treatment methods have been proposed: air abrasion, high output lasers or combined techniques. Objective: The objective of this study is to compare the etching patterns of various pre treatment techniques of enamel with conventional 37% phosphoric acid etchant, laser, air abrasion with and without activation under scanning electron microscope. Materials and Method: Forty extracted anteriors and premolars were allocated into 8 groups (5 each): (1) 37% phosphoric acid etching (2) phosphoric acid etching with activation (3) Laser etching (4) Laser etching with phosphoric acid etching (5) Laser etching with phosphoric acid etching with activation (6) Etching with air abrasion (7) Etching with air abrasion with phosphoric acid etching (8) Etching with air abrasion with phosphoric acid etching with activation. Results: In the laser-etched enamel preparations, surface layer was severely fissured and probably denatured, which gave rise to a more heterogeneous surface than that obtained by acid etching. The specimens conditioned with Er : YAG laser followed by phosphoric acid etching with activation resulted in a more homogenous surface pattern than others in the same group. Conclusion: Based on etching patterns observed on buccal surface of teeth , 37% phosphoric acid etching with activation gave better etching pattern (type 2) followed by laser etching with activation of etchant (type 1), air abrasion with etchant , air abrasion only, laser only. Keyword: Etching patterns, Air abrasion, Laser, Scanning electron microscopy.