This paper focuses on the efforts of one organisation to develop the organisational competences required to succeed in realising benefits from IS/IT investments. The case study takes the perspective that the development of competences for benefits realisation is a programme of organisational change. This perspective has been valuable and has helped identify a number of lessons for other organisations. Previous work on benefits realization from IS/IT has largely focused at the project level. The main contribution of this paper is to focus upon the management of benefits at the portfolio level, and then identify a number of areas in which portfolio-level practices might fruitfully be established. The study also makes a contribution to the developing literature on IS competences and capabilities by providing new insights into why it is as important to proactively manage IS projects at the portfolio level, as it is at the individual project level.