Infant feeding represents a great challenge in the prevention of mother-to-child transmission of HIV (pMTCT). The international guidelines informing infant feeding counselling suggest feeding methods that reduce the risk of HIV transmission, and discourage mixed feeding (combining breastfeeding with other fluids and solids). The feasibility and the social acceptability of the recommended feeding methods are hotly debated currently. Through the documentation of HIV-positive women's experiences, this article aims to provide empirically grounded knowledge on the relevance of the proposed feeding methods. Drawing upon cultural theory and a view of infant feeding practices as socially and culturally embedded, the article discusses the so-called 'informed choice' of infant feeding method among women enrolled in the pMTCT programme at Kilimanjaro Christian Medical Centre in northern Tanzania.The study is based on interviews and follow-up of 20 HIV-positive mothers during the last part of pregnancy, delivery and the first six months after birth. The article details four of these cases describing the challenges linked to exclusive breastfeeding, cow's milk feeding and formula feeding. The study demonstrates the gap between intentions and infant feeding practice in a context where the social expectations to breastfeed are high, and where kin and neighbours are part of the decision-making team surrounding infant feeding. It highlights the tension between the competing concerns of the medical and social risks involved in the choice of infant feeding method, and documents that the feeding options may be difficult to adhere to, whether a mother chooses exclusive breastfeeding or replacement feeding.