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Conservation agriculture's underlying principles—minimal soil disturbance, soil cover and crop rotation—are increasingly recognized as essential for sustainable agriculture. This article summarizes three contrasting cases of adapting conservation agriculture (CA) to smallholder conditions in the (sub)tropics: a) irrigated rice-wheat systems in South Asia; b) rainfed maize/wheat and irrigated wheat systems in Mexico; and c) rainfed maize in Southern Africa. In the South Asia case, farm surveys show rapid and widespread adoption of zero tillage wheat—primarily due to a substantial cost saving (15–16%). In the other cases, uptake so far has been limited—although long-term trials show continuously higher and more stable yields both for maize and wheat. Under marginal conditions CA can generate substantial yield increases—averaging some 50% over conventional smallholder maize yields of 1 ton per ha over 6 …