This paper combines the results of surveys carried out between 1995 and 2001 in Benin and Nigeria on farmers' practices in connection with the domestication of yams (Dioscorea rotundata), which is still an active process in West Africa. In Benin more than 500 yam producers belonging to four major yamproducing ethnic groups (Bariba, Mahi-Fon, Nago and Yom) and nearly 300 farmers in six different states of Nigeria were interviewed. The knowledge of wild yams is still alive even among farmers who have never domesticated yam. In the two countries the techniques described are very similar and the domesticated wild yams belong either to D. abyssinica in the northern part of the studied area (drier savanna zone) or to D. praehensilis in the southern part (humid savanna). The percentage of farmers who are domesticating or have recently domesticated yams varies from 3-14%. The domestication process mainly leads to early maturing cultivars, which are produced in double-harvest systems. The practice of domestication is decreasing, especially in the regions where commercial yam production is well developed.