BackgroundBreastfeeding has positive impacts on the health, environment, and economic wealth of families and countries. Nevertheless, barriers to accessing high-quality breastfeeding support are evident in the low global exclusive breastfeeding rate of 41%. The World Health Organization (WHO) launched the Baby Friendly Hospital Initiative (BFHI) in 1991 as a global program to incentivize maternity services to implement the Ten Steps to Successful Breastfeeding (Ten Steps). These were developed to ensure that maternity services remove barriers for mothers and families to successfully initiate breastfeeding and to continue breastfeeding through referral to community support after hospital discharge. However, in 2020 only 26% of Australian hospitals were BFHI-accredited. This study aimed to examine the social return on investment (SROI) of implementing the BFHI in one public maternity unit in Australia.MethodThe study was non-experimental and conducted in the maternity unit of an Australian BFHI-accredited public hospital with around 1000 births annually. This facility illustrated costs for BFHI implementation in a relatively affluent urban population, and more than three in four births in Australia take place in public hospitals. Stakeholders considered within scope of the study were the mother-baby dyad and the maternity facility. We interviewed the hospital’s Director of Maternity Services and the Clinical Midwifery Educator, guided by a structured questionnaire, which examined the cost (financial, time and other resources) and benefits of each of the Ten Steps. Analysis was informed by the Social Return on Investment (SROI) framework, which uses monetary values to measure social, environmental and economic outcomes of change. This information was supplemented with micro costing studies from the literature that measure the benefits of the BFHI. ResultsThe social return from the BFHI initiative in this facility was calculated to be AU$ 1,398,140. The total investment required was AU$ 24,433 per year. Therefore, the SROI ratio was approximately AU$ 55:1 (sensitivity analysis: AU$ 16-112), which meant that every AU$1 invested in BFHI implementation by this maternal and newborn care facility generated approximately AU$55 of benefit. ConclusionsScaled up nationally, the BFHI could provide important benefits to the Australian health system and national economy. In this public hospital, the BFHI produced social value greater than the cost of investment, providing new evidence of its effectiveness and economic gains as a public health intervention. Our findings using a novel tool to calculate the social rate of return, indicate that implementation of the BHFI is an investment in the health and wellbeing of families, communities and the Australian economy, as well as in health equity.