Aims: Breastfeeding significantly benefits mothers and infants. We aimed to identify the determinants of its successful initiation. Methods: A retrospective study of 1893 mothers delivering healthy term singletons at a Swiss university hospital from 1/2008 to 3/2009 determined the associations between multiple breastfeeding and early postpartum parameters by univariate and multiple regression analysis. Results: Multiparity was associated with nursing exclusively at the breast at discharge (P < 0.001), less use of maltodextrin supplement (P < 0.05), bottle/cup (both P < 0.001), but more pacifier use (P < 0.05). Among obese mothers, nursing exclusively at the breast at discharge was less frequent, and use of all feeding aids more frequent, than among normal-weight women (both P < 0.001). Neuraxial anesthesia was associated with use of maltodextrin and bottle (both P < 0.05) compared to no anesthesia. Delayed first skin-to-skin contact and rooming-in for < 24 h/day were each associated with maltodextrin and cup (P < 0.05). Nursing exclusively at the breast at discharge was less frequent (P < 0.001), and bottle use more frequent (P < 0.05), in women with sore nipples than in those without. Conclusions: Obesity is a potent inhibitor of breastfeeding initiation. Delivery without anesthesia by a multi parous normal-weight mother, followed by immediate skin-toskin contact, rooming-in for 24 h/day, and dedicated nipple care, provides the best conditions for successful early postpartum breastfeeding without the need for feeding aids or nutritional supplements.