Climate change fundamentally alters how we should manage agricultural systems for food security as clearly shown in the recently released IPCC Working Group II report on Food Security and Food Production Systems. Climate change is already threatening food systems and agricultural based livelihoods through a range of impact pathways, and these are likely to increase in the absence of adaptation. Agricultural growth is essential for increasing the availability and access to food, but historically such growth has resulted in significant increases in GHG emissions. The Climate-Smart Agriculture (CSA) approach was developed in 2010 in recognition of the need to address food security, agricultural development and climate change holistically. CSA was idefined as an approach to developing the technical, policy and investment conditions to achieve sustainable agricultural development for food security under climate change. This approach is now being piloted in three countries based on a process developed for a country-driven CSA methodology. This involves the development of an evidence base, dialogue and policy harmonization, investment analyses and links to climate finance. This brief lays out the methodology and the variation in its implementation across varying circumstances in the three countries. Strengths and weaknesses of the methodology are presented, as well as indicators of early outcomes. The paper provides insights into what will actually be needed to support broader implementation of the CSA approach.