Introduction: Hospitals are in a unique position to promote, protect, and support breastfeeding. However, the association between in-hospital events and breastfeeding success within population-based samples has not been well studied. Materials and Methods: A stratified (by education and birth weight) systematic sample of 5,770 mothers taking part in the Utah Pregnancy Risk Assessment Monitoring System, 2012-2015, were included. Mothers, 2-4 months postpartum, completed the 82-item questionnaire, including if they had ever breastfed their new baby, and if so, current breastfeeding status. Relationships between in-hospital experiences and breastfeeding termination and duration were evaluated via Poisson and Cox proportional hazard regression models, respectively, adjusting for other in-hospital experiences, maternal age, race/ethnicity, maternal education, marital status, smoking, physical activity, delivery method, pregnancy complications, and length of hospital stay. Results: Of all, 94.4% of mothers self-reported breastfeeding initiation, of whom 18.8% had breastfed