Steganography is the art of hiding the information that is going to be sent from one party to another. Information can be hidden into image, te xt, audio or video. Steganography allowed communication to happen without other people notice there is transmission of message except the intended party. This paper explains the implementation of Receiver Operating Characterictic (ROC) graph addressing the incorrect classification of images for stegogramme and non-stegogramme classes using Pairs Analysis detection technique. The threshold value to discriminate between the two classes is identified, to reduce the rate of False Negative (FN). © 2008 IEEE.