This paper examines agricultural intensification as a strategy for achieving sustainable livelihoods, comparing evidence from a number of areas that have undergone such a process-in particular, the introduction of Green Revolution methods. Noting the variable impact the Green Revolution has had on different regions, crops and individuals, it reviews the explanations for these differences provided in the literature. The paper outlines the key conceptual questions surrounding intensification, setting them within the context of the broader environment and population debate. Citing evidence from Africa and Asia that challenges the simplistic assumption that population growth and environmental degradation necessarily go hand in hand, it demonstrates the complexity of the processes at work and discusses the importance of institutional factors, such as land tenure, in determining whether intensification is sustainable in the longer term.