AbstractBreastfeeding promotion and support in hospitals is expected to have a positive impact on maternal breastfeeding outcomes. The objective of this study is to examine the association between breastfeeding promotion in maternity hospitals in Germany and exclusive breastfeeding (EBF) rates during the first 4 months. Thus, a nationwide cross‐sectional web‐based survey of breastfeeding promotion was conducted in 103 hospitals. Mother–infant pairs (n = 962) were recruited at these hospitals for a prospective web‐based survey of breastfeeding status at five‐time points, that is, during a hospital stay, at discharge as well as after 0.5, 2, and 4 months. The hospital analysis was based on the “10 Steps to Successful Breastfeeding” of the World Health Organization and the United Nations Children's Fund, adapted for Germany. Their degree of implementation was stratified by a breastfeeding promotion index (BPI) as low (≤5 steps), medium (6–8 steps), and high (≥9 steps). The association between the BPI and the odds of EBF at each of the five‐time points was estimated by multivariable regression models, adjusting for various maternal factors. At all time points, the proportion of EBF among mothers from high BPI hospitals exceeded the proportion of those from medium or low BPI hospitals. A high BPI was associated with higher odds of EBF during the hospital stay and at discharge, while maternal factors for EBF such as breastfeeding experience and no early use of a pacifier persisted beyond. The high commitment of hospitals and tailored support of mothers is essential for EBF.