Abstract This paper has investigated how the new national museum in Oslo has managed uncertainty over a three-year period (2016-2018). A combined approach was chosen for this study, using both a qualitative and a quantitative data collection method. We have collected data from the risk registers at two phases of the project – the planning phase (2010-12) and the construction phase (2013-18). Separate opportunity workshops as one the changes that made the project come back on track in terms of time and cost. Focusing on opportunity register for each of the contracts that is monitored and update every month had been quite successful and resulted in a balanced uncertainty register with 160 opportunities (estimated value 60 Mill. USD +/- 1.0 Mill. USD) and 166 threats (estimated value 78 Mill. USD +/- 10 Mill. USD) in the construction phase. The actual outcome on the opportunities/threats cannot be established at this point since the project is still running for one more year. But we will suggest that this approach most likely will bring much more opportunities in to the project and that the cost saving effect is considerable.