Journal of Digital Information Management Samir Bourekkache, Okba Kazar, Ahmed Aloui 17 3 2019 10.6025/jdim/2019/17/3/133-144 http://dline.info/fpaper/jdim/v17i3/jdimv17i3_3.pdf Today the security aspect is a backbone of every computer system, particularly when this system contains sensitive information. When we use our computers and connect to the network or use web services, we trust that our personal and sensitive information (images, passwords, credit card number ...etc) are confidential and well secured by the used security system. Unfortunately, the hackers may succeed to gain access to the system and misuse our information. Generally, the aim of the intrusion is to find new ways to annoy, steal and harm parts of computer systems. Moreover, with the possibility of connecting several computers and networks, the necessity of protecting the whole data and machines from attackers (hackers) that try to get some confident information to use for their own benefit or just destroy or modify valuable information was born. At this point IDS appears to help users, companies or institutions to detect when they are getting compromised. In this paper, we develop an intrusion detection system using multi agent system, ontological techniques (IDSMAO) and misuse method.