Climate change - and particularly its long term-implications - has become the greatest challenge that scientists and politicians have to face. The building sector worldwide and, more specifically, the existing building stock, have been identified as major contributors to both global energy consumption and environmental damage. This study aims at investigating the most appropriate measures for the refurbishment of the Architecture building of TU Delft (BK City) that, currently, lacks sufficient energy conservation measures and is characterized by its obsolete fabric and outdated building services systems. Moreover, the final proposals take into account the historical value of the building, along with its most essential features. The first part of the study is a theoretical approach to the problem that starts by defining the content of the terms ‘sustainability’, ‘refurbishment’ and ‘historic buildings’. Next, a framework of the ‘sustainable refurbishment of historic buildings’ in terms of legal, ethical and procedural aspects, is outlined, as well as the range of possible refurbishment measures that can be applied within this framework. After having analyzed the extent and severity of the problem with specific reference to Europe, this section ends by highlighting the potential of refurbishment and by providing a brief summary of the current status of well-known refurbishment policies in four European countries. The second part of the study is an investigation of the case-study building. Necessary information concerning the context of BK City is presented, ranging from climatic and geographical data, to specific information on the building, its history and its performance in terms of building physics. Here, the distinguishing features of the building are identified, as well as the permissible interventions. With regards to building physics, it is pointed out that the weaknesses of the building are, mainly, the out-dated exterior envelope and mechanical equipment, which result in a poor indoor climate, despite the excessively high energy consumption. The information in this section is essential for the development of the refurbishment strategies. Before elaborating on the refurbishment alternatives, an investigation is carried out to cluster all possible measures in 8 categories and cite relevant showcases and good practice examples of previously refurbished buildings. The most appropriate of these measures form the three proposed refurbishment Strategies of this Thesis, that range from basic interventions, such as cavity wall insulation, to more sophisticated solutions, as is the use of fuel cells. Advantages and disadvantages, application guidelines and market availability for each measure are provided. The objective of the last section is to evaluate the impact of a selection of the aforementioned measures. For this purpose, a model is provided that allows the static calculation of the heating and cooling demands that will keep the indoor climate of the building at comfort levels. The results of these calculations are further analyzed and discussed. The conclusions suggest that the existing building is wasteful in its use of energy resources and, thus, huge possibilities lie in its refurbishment, even if only moderate measures are applied.