This paper presents part of the preliminary results of a pilot research project commissioned by the Dutch research funder NWO, aimed at studying the current assessment of interdisciplinary research proposals at NWO and make possible recommendations for improvement based on the international literature. In the presented study a combination of document analysis, semi-structured interviewing and observation was used to study current assessment practices in the context of three different funding calls to which inter- or trans-disciplinary research proposals were submitted. Findings from the three calls were compared to best practices presented in the existing literature and used to make recommendations for possible improvements, reflect on possible barriers for effective reforms, and suggest further research avenues for a larger potential follow-up project.