Abstract In the paper project portfolio selection problem is considered. Both researchers, as well as practitioners agree that various criteria, including both quantitative and qualitative ones, should be taken into account when the project portfolio is constructed. Various decision aiding techniques dedicated for project portfolio selection problems are proposed in literature. Most of them assume that the information about the decision-maker's preferences is collected before starting the calculation procedure. Several criticisms have been expressed against such approach. The assessment of the sufficient a priori preference information is inconvenient and time consuming. Moreover, as the decision maker is not employed in the second phase of the procedure, when the final solution is generated, so he/she may feel excluded from the important part of the analysis and put little confidence in a final result. In the paper a concept of a new methodology based on interactive approach is presented. It assumes, that a single portfolio is proposed to the decision maker in each iteration. The decision maker evaluates the proposal, thus indicating how to improve the solution. A simple example is presented to explain how the dialog with the decision maker can be carried out.