Environmental sustainability has become an urgent matter on the Dutch political agenda, which will affect the built environment in the near future. Consequently, organizations have to adapt their real estate to new regulations for building performance and their own sustainability goals. The Preference-based Accommodation Strategy (PAS) is a decision-making strategy that aids organizations in finding a Corporate Real Estate Portfolio (CREP) that aligns with the organization’s values. This research aimed to stimulate organizations to improve the environmental sustainability of their CREP by changing the decision-making process. Therefore a sustainability reference model (SuRMo) was developed for PAS and tested on the CREP of Colliers, an international real estate consultancy firm with multiple offices in the Netherlands. In the pilot study, PAS and the SuRMo were used to evaluate three alternatives for a new office space in Utrecht. In an iterative process using the operation research methodology four tests were conducted which compared the outcome of the different decision-making processes. The four tests analysed 1) the current decision-making process, 2) the decision-making process and outcome using PAS, 3) the decision-making process and outcome using PAS with the SuRMo 2.0 and 4) the sustainability performance of Test 1-3 compared to Dutch sustainability goals for 2050. In the three tests the decision outcome resulted in the same office building that performed best in terms of environmental sustainability and matches the governmental goals for 2050. However, between Test 1 and Test 2 the total number of criteria increased from 7 to 37 and from two implicit environmental sustainability criteria to five explicit criteria. The outcome of this research shows that PAS increased the number of environmental sustainability criteria and changed the decision-making process of Colliers from implicit to explicit. The stakeholders expressed the need for the SuRMo because they lack knowledge about environmental sustainability in CREP but concluded that it requires further development for user-friendliness and suitability with PAS. The three actionable conclusions for practise are that PAS should be used in decision-making about CRE with a further developed SuRMo, Green Building Rating Systems should be used for sustainability in CRE decision-making instead of greenhouse gas emissions and project developers and investors can use the explicit outcome of PAS to adapt the supply to the demand on the real estate market.