In recent years large-scale agricultural input subsidies have had a contested ‘rehabilitation’ in sub-Saharan Africa. This paper reviews the changing paradigms, politics and theories associated with input subsidies’ decline and rise, and the implementation and impacts of recent large-scale programmes. Empirical evidence is patchy, and their impacts contested and dependent on context, design and implementation. Few programmes have lived up to expectations or achieved acceptable benefit cost ratio estimates. The paper discusses how such programmes can improve and realise their full potential, to deliver major dynamic benefits to smallholder farmers and the wider economies of which they are a part.