Glass/polyester and glass/epoxy laminated composites widely used in structures and have very near properties. These composite laminates have poor inter-laminar fracture resistance and suffer extensive damage by delamination cracking when subjected to out of plane loading and hence are vulnerable to delamination. The presence of delamination in the composite material may reduce the overall stiffness. Structural design and nondestructive test techniques have evolved as increased emphasis has been placed on the durability and damage tolerance of these materials. There are several methods used to investigate damages of composite materials. Acoustic emission is one of these. In this work the effect of delamination propagation on acoustic emission (AE) events in glass/polyester and glass/epoxy composites is obtained also Fracture surface examinations were conducted using a scanning electron microscope (SEM) and results in these two common composites compared. Consequently, revealed that the AE technique is a practicable and effective tool for identifying and separating kinds of cracks in these composites.