This paper presents a rule-based decision support system (DSS) for facilitating the adoption of the most appropriate multicriteria analysis (MA) method in solving information systems (IS) project evaluation and selection problems. A knowledge base consisting of IF-THEN production rules is developed for assisting with a systematic adoption of the most appropriate MA method through considering the decision maker’s requirements in project selection with the efficient use of the powerful reasoning and explanation capabilities of DSS. The idea of letting the problem to be solved determines the method to be used is incorporated into the DSS development. As a result, effective decisions can be made for solving the IS project evaluation and selection problem. An example is presented to demonstrate the applicability of the proposed DSS for solving the problem of evaluating and selecting IS projects in real world situations.