This study explores how farmers in three different communities of Nepal are influenced by the establishment of community seed banks (CSBs). Their effectiveness as an in situ conservation strategy is evaluated by assessing, through semi-structured questionnaires, focus groups and key informant interviews, the changes perceived by those involved in CSBs. These evaluations were put in context of the stated target areas of community seed banks and community-based biodiversity management (CBM): on-farm plant diversity, household economic and livelihood gains and increases in community welfare, organisation and autonomy. Findings suggest that in these respective areas: (i) Access to seed encouraged farmers to experiment with different varieties and their alternation over time. (ii) Greater household-level income and access to loan mechanisms appears to have provided an economic incentive to maintain local crop diversity. (iii) The tasks inherent to planning, forming and running a CSB creates a space which necessitates the intensification of local social cooperation and mutual learning. Aggregate social benefit and greater autonomy from both input pressures and market dynamics appears to be an emergent property of this cooperation. A secondary aim of this study was to devise the first, to our knowledge, framework for the evaluation of CSBs. After a review of CBM, CSBs and on-farm conservation strategies, we propose their integration with agroecology as a theoretical construct that is able to unify all of their respective approaches and values, as well as weaknesses and contradictions, reflecting the needs of, and potential pressures, on present and future generations of Nepalese smallholders.