The very idea of intrusion detection can be perceived through the hasty advancement following the expansion and revolution of artificial intelligence and soft computing. Thus, in order to analyze, detect, identify and hold up network attacks a network intrusion detection system based on rough set theory has been proposed in this article. In this paper we have shown how the rough set technique can be applied to reduce the redundancies in the dataset and optimize the Intrusion Detection System (IDS). © Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2013.