The D4R Challenge provided anonymized mobile phone data from Turk Telekom to participating researchers to help them create innovative approaches to support more than 3.5 million refugees living in Turkey. In particular, the organizers prioritized the areas of security and safety, health, education, unemployment and social integration. Through the Data For Refugees challenge, three anonymized call detail record datasets, two files on cell tower locations and one year of mobile CDR data were made available to help researchers. The challenge was judged by a committee of international experts on data and humanitarian issues.