This article analyses how the events of the late 1960s – and in particular the Nigeria–Biafra War – marked a turning point in the history of the International Committee of the Red Cross (ICRC). The Nigeria-Biafra conflict required the ICRC to set up and coordinate a major relief operation during a civil war in a post-colonial context, posing several new challenges for the organisation. This article shows how the difficulties encountered during the conflict highlighted the need for the Geneva-based organisation to reform the management of its operations, personnel, and communications in order to become more effective and professional. Finally, the article takes the examination of this process within the ICRC as a starting point for a broader discussion of the changing face of the humanitarian sector in the late 1960s. Keywords: Nigeria, Biafra, ICRC, history, professionalisation, reform, assistance.