Abstract. Information retrieval (IR) systems are used for finding those documents, which satisfy user information need. By such a great increase of documents in the Internet, income of information in databases, precise and quick retrieval of relevant documents is of great significance. Artificial intelligence methods can be essential for achieving this goal. The article describes one of such methods -a model of IR based on Bayesian networks. Usage of the network and an experiment aiming in showing that using this method improves information retrieval is presented. An emphasis was made on the benefits of using the Bayesian networks and the way of adapting such a network to information retrieval system is presented.