Given that contractor plays a critical role in any construction project, contractor selection constitutes key decision for public authorities. Prequalification, i.e. the elimination of incompetent contractors from the bidding process according to a predetermined set of criteria, is a frequently practiced procedure in many countries, including Greece. In order to enhance the performance levels of selected contractors and to minimize failures in meeting client’s objectives, several criteria must be taken into account and a consistent evaluation methodology must be applied. We propose a multicriteria decision making approach, based on the Analytic Hierarchy Process (AHP), for supporting public authorities in contractor prequalification. The decision problem is decomposed into qualitative criteria and sub-criteria that are further analyzed in quantitative indicators on which the candidate contractors are evaluated. Our advisory decision support system is an appropriate tool for at least three reasons: First, various criteria are included, in order to ensure the quality of the completed product. Second, it is easy to use, because, on the one hand, it requires no prior knowledge of multicriteria methods from the potential users; and, on the other hand, it minimizes subjective judgments. Finally, the model minimizes the required pairwise comparisons, which is considered to be a major default of AHP.