ABSTRACT Public bidding is a Brazilian subject of great importance, being subject to control by the federal audit court, to prevent deviations and corruption. Even national legislation has undergone recent changes to make the use of this instrument more effective. In the public aspect, the bidding process goes through the determination of the need, the publication process, the choice, the contracting, and the post-contract period. Since some of the bidding modalities are exclusively based in “lowest price” and prevent the direct use of MCDA selecting the alternatives, this paper proposes using a combined approach, using MCDA and cognitive maps, to help in the determination of the bidding object. This approach is applied to a hypothetical situation, and the case study shows the convenience of its practical use in a real situation. The specific case is related to structural covering, using NBR15575 as a criteria definition subsidy. The study shows a contribution of cognitive maps to express the rationale according to legal principles and providing elements of the MCDA model. While FITradeoff supports the definition of the object, which is fundamental to avoid failures in the contracting process. The recent FITradeoff web version is used and the advantage of using the method is the reduction of decision-maker biases, increasing the transparency of the process. importance court corruption effective aspect need choice postcontract post contract period lowest price alternatives object situation covering NBR NBR1557 subsidy model decisionmaker decision maker biases NBR155 NBR15 NBR1