Yam and cowpea are important elements in the food culture of local communities in the Transitional Guinea-Sudan Zone of Benin. Yam and cowpea serve to satisfy vital needs in households and in communities, but also play an essential role in the rituals and ceremonies of the agrarian civilizations of Benin. The diversity of rituals, food habits, technological traits and food security strategies for the two crops contributes to the maintenance of varietal diversity. It is not possible for one or even a few varieties to meet all needs. The more a variety is culturally and socially embedded, the greater the chance that it will meet acceptance on the local and regional market. Farmers' ambition to meet market demands in order to satisfy socio-economic needs also sustains and increases varietal diversity. Especially female farmers growing cowpea showed positive diversity maintenance behaviour. Overall, the study shows that the management of on-farm genetic resources is a socially and culturally constructed system. Any external strategy to improve management of on-farm diversity should take into account these social and cultural aims.