_Abstract: There are many railway station buildings of the 19th and 20th centuries in Portugal that are now vacant and/or obsolete. Some of these buildings are not in use, because those buildings were replaced by new technology. In a country where the urban park is overloaded, the need for implementing sustainable refurbishment and requalification is essential. The issue of this thesis is to study strategies of sustainable rehabilitation of former railway stations. The study will include the analysis of a case study the Sacavem, which will be transformed into environmental NGO premises. Design solutions will proposed, having as basis the evaluation system LiderA, solutions of passive design will be explored in order to obtain a good energy performance.