Over 70 million people are forced migrants displaced by conflict, political upheaval, violence and disasters but also by climate change and development projects. Although rapid-onset events such as conflict or disaster may be the immediate reason forcing people to leave their homes, the search for better economic opportunities, slow-onset and progressive environmental deterioration, increasing suppression of rights and the availability of family networks in more stable locations may determine precisely where they move and for how long. This report considers changes in the circumstances that make populations vulnerable to forced displacement, and further vulnerabilities to which forcibly displaced people are exposed. It draws attention to the diverse health needs of forced migrants as a result of the combination of acute and chronic threats to health, and stresses the importance of enhancing professional standards and mainstreaming the health care of displaced persons. It advocates making reproductive, maternal, mental and child health a strategic and operational priority. The report also highlights how forced migration has ‘urbanised’. Cities, towns and peri-urban areas are the main destinations for refugees, internally displaced persons, and people affected or impacted by disasters and conflicts. Urban displacement affects the displaced themselves, but also the populations they settle among, particularly where unplanned urban development has lead to poor provision of infrastructure and services. However, movement to the city may help the displaced to mitigate vulnerability that stemmed from the cause of their displacement. The report draws attention to the role of development as a major, but often ignored, driver of forced displacement. As well as recognised economic benefits, development can also cause impoverishment and social fragmentation for some. Industrial, agricultural, and urban renewal projects can force individuals to relocate, as can economically powerful interests. The report recommends increasing the links between humanitarian and development actors to improve the humanitarian response to forced displacement by involving both development and humanitarian approaches in planning for resettlement as a result of development. Recommendations for responding to the challenges of forced migration focus on four dimensions: the organisational architecture of the international humanitarian response; enhancing the role of community-based responses; solving protracted displacement; and the relationship between climate change and displacement.