The goal of this project was to promote breastfeeding among infants with congenital heart disease in a quaternary care academic children's hospital. We aimed to increase the total number of breastfeeding episodes among all patients in the Pediatric Cardiac Transitional Care Unit with implementation of pre- and post-breastfeeding (test) weights. Infants with congenital heart disease are able to breastfeed, but are often not encouraged to do so by healthcare providers. Fears and concerns relating to the inability to account for exact intake volumes through breastfeeding often prevent providers from supporting breastfeeding in these patients. This project used Joanna Briggs Institute's Practical Application of Clinical Evidence System (JBI PACES) and Getting Research into Practice (GRiP) audit tool for promoting health practice change. A baseline medical record audit was conducted, followed by staff nurse education on breastfeeding test weights and the development of a parent education program. One follow-up audit measured compliance with best practice criteria for using breastfeeding test weights in infants with congenital heart disease. Compliance rates for use of breastfeeding test weights and provision of parent education, with baseline rates of 7% and 0%, respectively, rose to 90%. Identification of maternal intent to breastfeed upon admission to the unit increased to 78% compliance from 0%. Eighty-four percent of healthcare staff were educated on breastfeeding test weights. The safety of breastfeeding very ill infants was established. Breastfeeding episodes of all patients in the unit significantly increased after implementation of breastfeeding test weights and mothers of the sample patients expressed more confidence in breastfeeding their sick infants. Although barriers to breastfeeding for patients with congenital heart disease still persisted, this project had a positive impact on the culture of breastfeeding within the project unit. Increased healthcare provider education on breastfeeding will be essential to sustaining outcomes of this implementation.