With an increasing body of scientific evidence showing the sustainability issues have been catapulted to the very top of the global political agenda. Governments and societies around the world are becoming increasingly united on the need to reduce the negative environmental effects. As a result there is an ever increasing range of regulatory and taxation measures, as well as voluntary initiatives, designed to help reduce environmental damage. In terms of real estate there is a lot of research into sustainability on property level. There is research on the needs of the property occupiers as well as different kinds of assessment criteria, certificates and standards on the property level. Nevertheless overall accepted standards have not been reached. In contrast to property level, portfolio management as well as investment decision making process have not been regarded in depth by academic research. There is a need to develop criteria for property companies to assess the sustainability of the whole property portfolio level. The aim of the paper is to study the current situation of the sustainability assessment practices in property companies. The research is based on theme interviews with selected German and Finnish property companies and multidisciplinary literature review. The paper presents the current situation of property sustainability assessment; practices, requirements and needs for property portfolio assessment criteria. In addition, the business benefits of the sustainability assessment for the property companies are discussed