Sustainability continues to gain relevance in the real estate sector. More and more owners and investors are requesting information and advice concerning sustainability features of their properties. This development represents a challenge to property valuation. Valuation professionals are requested to take a stand if and how sustainability influences property valuation (including the need for quantification, respectively). In order to answer these questions an operationalization of the concept of sustainability in regard to property valuation is required. This is further complicated by the lack of mutual understanding and established standards regarding sustainability in the real estate sector. Since valuation professionals are increasingly confronted with these questions in their daily work, there is an urgent need for clear and practicable guidelines. In Europe or even internationally there are currently no signs of standard solutions any time soon. A group of scholars have started as a private initiative to develop respective sustainability guidelines for Germany, Austria and Switzerland with the support of several valuersí associations. Apart from generic guidelines, the manual includes a long-list of value-relevant property features including sustainability features, a discussion of how sustainability features can be included in the most common valuation methods and guidelines on the quantification of the impact of sustainability features on property value. First results will be presented in the paper.