Considerable efforts are being directed at tackling the problem of cassava viruses in Africa. Yet these efforts are not fully coordinated, and the overall scale of mitigation programmes is tiny compared with the scale of the threats to the world’s cassava crop. With this in mind, the Global Cassava Partnership for the 21st Century (GCP21), a recognised global organisation within the cassava community, gathered representatives from 24 research and development (R&D) organisations and donor agencies at the Rockefeller Foundation Center, in Bellagio, Italy, on 5–10 May 2013. The workshop established a Global Alliance to Declare a War on Cassava Viruses in Africa, to develop a strategic action plan. The resulting road map lays out three primary objectives: to prevent cassava brown streak disease from reaching Central and West Africa (the largest cassava regions in Africa); to mitigate the effects of these constraints on cassava in parts of Africa already affected; and to prevent the spread of cassava mosaic disease and cassava brown streak disease to the rest of the world.