This paper reports the results of a systematic review of the impacts of climate change on crop productivity in Africa and South Asia. The study, funded by the UK Department for International Development (DFID), assessed eight food crops — rice, wheat, maize, sorghum, millet, cassava, yam, plantain and sugarcane — that make up more than 80 per cent of agricultural production in these regions. Its findings aim to inform DFID's policies, allocation of resources and other practices according to the need for a stronger focus on evidence-informed decision-making on agriculture in a changing climate. The report provides background information; a detailed account of the review protocol and methodology; the data extraction strategy; data collection; meta-analyses; a synthesis of results; and key findings for all crops organised by region. It recognises that climate change will worsen environmental conditions that already affect crops, such as heat, drought, salinity and submergence in water.