In early 2016, a cache of Islamic State (IS) foreign terrorist fighter (FTF) records was leaked. It was subsequently obtained by a handful of media outlets and academic institutions, including the International Centre for the Study of Radicalisation (ICSR) at King’s College London, where I spent a year and a half working as a Visiting Research Fellow. This report takes an in-depth look at the leaked documents, focusing in particular on the citizens and residents who originated in Saudi Arabia.The documents contain a wealth of personal information regarding those who joined the terrorist group in Syria at a time when its appeal was at its greatest. While these documents give us neither the whole picture of the organisation’s structure, nor the complete number of its recruits, they are important because they provide us with a recruitment snapshot from a crucial period in recent history. They also provide valuable insights into the profile of local recruits, their travel flow, and the IS mobilisation infrastructure.