Green Public Procurement (GPP) can play a significant a role in efforts to influence the private sector towards more sustainable products and services. Following an account of the environmental impact of Nordic public procurement, the project provides an assessment of the potential of strengthening GPP within three key product groups in Nordic public procurement: Taxi and coach services, Computers and related services, and Cleaning products. The analyses show that compared to traditional regulatory instruments GPP tends to be more soft and dynamic - but also slower and less comprehensive. A decision model for GPP is developed. Two cases illustrate the potential benefits of GPP: Procurement of a new server centre in the City of Copenhagen, and procurement of transportation for disabled and elderly people in the City of Stockholm. Conclusions and recommendations on how to strengthen the benefits of GPP are provided. The study has been initiated and supervised by The Working Group on Environment and Economics under the Nordic Council of Ministries.