This paper summarises findings from a two-year study examining aid in insecure environments. Drawing on the most comprehensive global dataset to date of major reported incidents of violence against aid workers from 1997 to 2005, it provides a quantitative analysis of the changing security environment for civilian aid operations. It then examines the related trends in policy and operations over the last decade, in particular how perceptions of increased risk to aid operations have affected the development of security measures. Lastly, it explores the way in which aid operations have adapted to working in highly insecure contexts through a growing reliance on national staff.