There is global interest in promoting mitigation and adaptation in agriculture, forest, and other land-use (AFOLU) sectors to address the twin goals of climate change and sustainable development. This guideline deals with how to enhance carbon stocks in general in all land-based projects and its specific relationship with agriculture productivity. It outlines specific steps and procedures that need to be followed by project proponents and managers of land-based projects to enhance carbon stocks synergistically with increasing crop productivity. This guideline for carbon stock enhancement or CO2 emission reduction in agriculture and natural resource management (NRM) projects covering all land-use sectors presents two approaches. The first approach is a generic one covering all the land categories and interventions aimed at promoting the economic benefits (crop, timber, and non-timber wood product production, and employment or livelihood generation) and environmental benefits (soil and water conservation, land reclamation, and biodiversity protection) of a project, synergistically optimizing carbon stock enhancement as a co-benefit. The second approach provides guidelines for project developers to maximize project C-benefits along with promoting high-value cropping systems and production practices appropriate for a given agro-ecological region as well as to meet the needs of the local stakeholders, such as farmers or landless laborers. An illustration of the two approaches is presented at the end of the executive summary. The guidelines provide methods for selection and incorporation of carbon stock enhancement modules and practices along with methods for estimation and monitoring of carbon stock changes as well as assessment of social and economic implications of carbon enhancement (C-enhancement) interventions.