© 2018 The Author. IDS Bulletin and Institute of Development Studies. Recent years have witnessed a renewed interest in integrated rural development (IRD) projects, which were a common feature of international development in the 1960s and 1970s. In this article we critically review the literature on past IRD with the goal of informing current practice. We identify two key narratives in the IRD literature: (1) IRD projects were designed to exploit complementarities and synergies between development interventions, and (2) the administrative complexity of IRD projects prevented their successful implementation. We argue that the first narrative is not grounded in a solid theory of how IRD works, and that the second is largely based on a body of evidence which is wide but not rigorous. We show that some recent IRD experiences have been successful and conclude that future IRD evaluations need a novel conceptualisation of synergies and greater attention to the characteristics of implementation and cost-effectiveness.