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.