In low-resource areas of West Africa where infant feeding patterns are dominated by prolonged breastfeeding, the prevention of mother-to-child HIV transmission requires new feeding practices: formula feeding or exclusive breastfeeding limited to six months followed by rapid weaning. Both patterns are innovations for the majority of women in all social categories at the local level. As innovations, these practices are applied only under certain conditions met by mothers; they also have social consequences. Two ethnographic studies conducted in 1998-2000 and in 2003-2007 explored women's perceptions about “good infant feeding” with implications for “good mothering,” and the social relationships that are involved in infant feeding management in a setting shaped by patrilinear organization. Women must rely on a range of strategies to face difficulties related to the lack of economic or social autonomy or support from the child's father, the risk of stigma, social norms regarding breastfeeding and contradictory discourses among health workers. HIV-positive mothers' experiences bring to light several key features of local infant feeding cultures, including the changes that occurred over the last ten years regarding the fathers' role, the impact of infant feeding conceptualization in biomedical institutions and the promotion of a model of infant care based on the dual mother-and-child relationship. These dimensions are considered in relation to general social trends in a West-African society regarding women's autonomy, the role of the couple in the household and the medicalization of infant feeding.