Guinea yam (Dioscorea rotundata Poir. and Dioscorea cayenensis Lam.) is a na­tive, old and traditional crop of West Africa. A long history of cultivation combined with high genetic diversity has led to important indigenous knowl­edge that needs to be documented. In Benin, farmers' expertise in adapting agricultural practices and landraces to local environmental constraints is remarkable. In order to document farmers' knowledge and strategies in managing diversity of yam landraces, a survey was conducted in the whole yam production zone of the country. Seventy villages and 11 major ethnic groups were covered. More than 310 distinct local varieties were recorded. Information was collected using both key-individual interviews and group discussions. Each variety was charac­terized on the basis of agronomic, post harvest and organoleptic attributes. From the farmers statements it appears that food quality (overall ability to give good pounded yam), yield, earliness, market value, storage ability and seed quality are the major preference criteria. Information gathered will assist the na­tional yam genetic research programme to formulate appropriate strategies for participatory breeding and in situ on farm conservation.