Aim: To evaluate microleakage in class II cavities using different composite materials and adhesive strategies under CLSM. Materials and methods: Standardized class II cavities (MO) were prepared in found sound extracted human upper premolars. The cervical margin of the proximal box was located at 1mm occlusal to the cementoenamel junction (CEJ). The prepared teeth were divided into two groups of 20 teeth each and then each group was subdivided into two subgroups of 10 teeth each. The samples of subgroup I1 and II1 (n=10 each) were subjected to etching process using 3M ESPE Scotchbond Universal etchant followed by bonding with the Adper Single Bond Plus Adhesive (3M ESPE, St Paul, MN, USA) bonding agent. The samples of subgroup I2 and II2 (n=10 each) were subjected self-etch adhesive strategy by applying Adper™ Easy Bond Self-Etch Adhesive (3M ESPE, St Paul, MN, USA). Then, all the samples in Group I were restored with Filtek™ Z350 XT Universal Restorative composite resin by using oblique increment technique with approximately 2 mm thickness.The samples in Group II were restored with Filtek™ Bulk Fill Posterior Restorative composite resin in a single increment of 4 mm thickness. All the restored teeth were stored in distilled water for 24hrs at room temperature, thermocycled and then soaked in Rhodamine B dye for 48 hrs. Teeth were then sectioned for evaluation of microleakage along the tooth-restorative interface in the occlusal and gingival regions using a CLSM. Data were collected and statistically analyzed using Kruskal-wallis one way analysis of variance (ANOVA) and Mann-Whitney U-test. Results: Statistically significant difference was observed in microleakage scores for occlusal and gingival margins between the subgroups of Group I and Group II using Kruskal - Wallis one way analysis of variance (ANOVA) test. The self-etch bonding strategy recorded a significantly more dye penetration with highest mean score (1.96 ± 0.79; P<0.001, 1.89 ± 0.64; P<0.001)) when compared to etch and rinse bonding strategy (1.54 ± 0.61; P<0.001, 1.56 ± 0.78; P<0.001)) in Group I and Group II respectively. The Mann-Whitney test was performed to evaluate significant differences of occlusal mean scores and gingival mean scores between subgroups but the results were not statistically significant within each subgroup though the microleakage mean scores were higher at gingival margins when compared to occlusal margins. Conclusion: All the test groups showed some amount of microleakage regardless of the test material or location of the margin or placement technique. Microleakage scores are higher at gingival margin compared to occlusal margin. Nevertheless, Etch and Rinse adhesive could be considered as the adhesive strategy of choice in class II situations in majority of cases as it showed low microleakge scores compared to Self-Etch adhesive strategy.