||Several Western urban development practices witness an increasing role of property developers in initiating, financing, and leading urban development projects. Moreover, local authorities have taken on an entrepreneurial facilitating attitude towards spatial planning. This situation is driven and strengthened by global neoliberalism and subsequent government retrenchments (Hackworth, 2002). Market-oriented planning (Adams & Tiesdell, 2010) and a focus on development projects have become commonly used planning policy implementation strategies in several countries. These forces, amongst others, resulted in the coming into being of private sector-led urban development projects, a concept introduced by Heurkens (2010). This development approach has occurred in the Netherlands since the 2000s, partly based on Anglo-Saxon development traditions in the United Kingdom [UK]. As a result, the relationship between, and roles of, public and private actors are shifting fundamentally. Hence, such new relations have resulted in public-private partnership challenges in the historically public-led Dutch development practice. Despite the vast amount of literature on the governance of Western planning practices (e.g. DiGaetano & Strom, 2003), remarkable little knowledge exists about what the shifted relationship means for the actual day-to-day management by public and private actors of urban development projects. Hence, it is such direct steering that brings about the most significant change to the built environment (Klijn, 2008). Moreover, limited knowledge is available about the project effects (e.g. collaboration effectiveness, process efficiency, product quality) of these partnership arrangements. This paper generates an understanding of the collaborative and managerial mechanisms, and development effects of private sector-led urban development projects. It does so by comparing the Dutch and UK institutional development practices, and by drawing empirical lessons from cross-case study research in both countries. In addition, it provides recommendations for a new perspective for local authorities to safeguard public interests, and for property developers to alternatively finance projects, aligning with the current social-economic context (Parkinson et al., 2009). References Adams, D. &, Tiesdell, S. (2010). Planners as market actors: Rethinking state-market relations in land and property. Planning Theory & Practice, 11(2), 187-207. DiGaetano, A., & Strom, E. (2003). Comparative urban governance: An integrated approach. Urban Affairs Review, 38(3), 356-395. Heurkens, E.W.T.M. (2010). Private sector-led urban development. Real Estate Research Quarterly, 9(2): 29-34. Klijn, E.-H. (2008). Itís the management, stupid!: About the importance of management in complex policy matters (Inaugural address). Den Haag: Lemma. Parkinson, M., Ball, M., Blake, N., & Key, T. (2009). The Credit Crunch and Regeneration: Impact and Implications. London: Department for Communities & Local Government.