In the Netherlands a guideline for carrying out a CBA for infrastructure projects (the so-called OEI-manual) was constructed in the year 2000. Since then a CBA in line with the OEI-manual became compulsory in the decision making process for all large infrastructure national projects. The aim of this research is to define the main problems in the current Dutch practice as experienced by three different groups: scientists, consultants, policymakers. Using semi-structured interviews 72 respondents were asked to discuss the five most important substantive problems they experience with CBA. In addition the respondents were asked to elaborate on the main advantages and disadvantages they experience with the use of CBA in the appraisal of spatial-infrastructural projects. Next they were asked to outweigh the advantages and the disadvantages. The main finding of this research is that both the majority of scientists, consultants and policymakers evaluate the use of CBA as an ‘ex ante’ analysis of spatial-infrastructure projects positive. In spite of this positive overall evaluation, the respondents experience 68 different categories of problems. This paper elaborates on the 68 problems. The paper also focuses on the differences between the three groups in relation to the problems they experience. The relation between ‘the number of respondents that mention a problem that can be assigned to a main category of problems’ and ‘group of respondents (consultant / scientist / policymaker)’ is tested. This relation is significant for the categories ‘Problems with welfare economics as fundamental theory of ‘ex ante’ evaluation instrument’ and ‘Problems with presenting conclusions’. Relatively few consultants and relatively many policymakers mention that they experience problems with welfare economics as fundamental theory of an ‘ex ante’ evaluation instrument and the number of consultants that experience problems with presenting conclusions is relatively low compared to policymakers and scientists.