Acoustic Emission (AE) generated during drilling of composites consists of sources like matrix deformation, fiber cutting, friction mechanisms, delamination and toolwear. Attempts made to identify the characteristics of these individual sources in terms of AE are presented here. An ultrasonic C-scan is utilized as an off-line technique for detecting and imaging the extent of delamination in the drilled Glass Fiber Reinforced Plastic (GFRP) laminate.