Introduction: The present study was done to evaluate microbial adhesion on the critical surface of different brackets. Objectives: Evaluation of microbial adhesion on the critical surface of different brackets. Methods: The study was conducted on ten different types of commercially available orthodontic brackets. They were catego rized into Group 1 and Group 2. Twenty-five MBT (0.22__ampersandsigntimes;0.28 slot) upper right premolar brackets were tested in each group. All the brackets were tested without any kind of ligation. CFU was calculated in both groups. Results: Adhesion of aerobic bacteria to Group I brackets are statistically significant (p0.05). Adhesion of anaerobes to Group II brackets was statistically significant (p0.05). Statistically, significant correlation found between Group IA, ID, IE brackets towards affinity of aerobic and anaerobic bacteria. Adhesion of aerobic and anaerobic bacteria to Group II brackets were statistically significant (p__ampersandsignlt;0.001). Conclusion: On comparison of aerobes and anaerobes present study was found that significant correlation between adhesion of aerobes to Group I __ampersandsignamp; II brackets whereas no significant correlation found between adhesion of aerobes __ampersandsignamp; anaerobes to Group IB __ampersandsignamp; IC brackets.