This report summarizes the findings of a multicountry study examining the impact of breast milk marketing on infant feeding decisions and practices, which was commissioned by WHO and UNICEF. The research study – the largest of its kind to date – draws on the experiences of over 8500 women and more than 300 health professionals across eight countries (Bangladesh, China, Mexico, Morocco, Nigeria, South Africa, the United Kingdom and Viet Nam). It exposes the aggressive marketing practices used by the formula milk industry, highlights the impacts on women and families, and outlines opportunities for action.