These guidelines outline the process for preparing a National Plan for Conservation and Sustainable Use of Farmers' Varieties/Landraces, in support of national authorities seeking to develop a systematic approach to the management of these genetic resources. They focus on the common elements required to ensure a systematic, national approach to conservation and sustainable use of farmers' varieties/landraces. The cultivation of diverse farmers' varieties/landraces, which tend to be well-adapted and suited to local production systems, confers increased resilience for crop production. Unfortunately, many of these genetic resources have been replaced by modern cultivars in recent decades, resulting in a reduction in the number of varieties grown and/or loss of heterogeneity. Such losses make farming systems less resilient, especially to shocks from abiotic and biotic stresses. These guidelines will contribute to addressing this continuing loss of diversity. They are a useful tool for development practitioners, researchers, students and policymakers who work on the conservation and sustainable use of these valuable resources.