The purpose of this paper is to investigate and compare in what ways different types of integrative and collaborative procurement strategies may enhance efficiency and innovation in public infrastructure projects. Further, implementation challenges are identified and discussed. Interview-based case studies were performed of ten infrastructure projects in Sweden and the Netherlands. The projects involve four types of collaborative procurement strategies - collaborative Design-Build (DB) contracts, Early Contractor Involvement (ECI) agreements, Design-Build-Maintain (DBM) contracts and Design-Build-Finance-Maintain (DBFM) contracts. The findings indicate that the duration of the collaboration is fundamental in setting the limits for innovation and that early involvement as well as long-term commitments open up for more innovation. Naturally, the potential for increased efficiency is higher than for innovation and also occurs in collaborations with limited duration. These integrated project approaches, however, still appear to be in an early stage of learning. For a public repeat client to realise the full potential of a new strategy, it is important to have a long-term perspective and capabilities to analyse and learn from the experiences.@en