Britain has one of the lowest breastfeeding rates in Europe, with particularly low rates among White British families living in disadvantaged communities. As breastfeeding has important long-term health benefits for babies and their mothers, this represents a serious inequality in health. It is part of the remit of Sure Start Children’s Centres which serve disadvantaged areas to offer child and family health services, including breastfeeding support. This study utilised an action research strategy to involve stakeholders in developing and extending breastfeeding promotion and support within three Children’s Centres in Bristol. A total of 10 focus groups were conducted with Children’s Centre staff and local parents between July 2008 and May 2009. Stakeholders’ views were explored on current breastfeeding promotion and how Children’s Centres could better support breastfeeding to meet local needs. Barriers to breastfeeding promotion were identified as latent hostility in the local community towards breastfeeding, and lack of knowledge about infant feeding among staff. Following implementation of the proposed changes, staff, parents and researchers shared their views on what had been achieved and on possible future initiatives. While there was variation in the extent to which Children’s Centres engaged with the action research process, and in the extent to which change was made, all Centres did develop their breastfeeding promotion practice. Initiatives put into practice included strengthening links with health professionals, actively seeking to involve fathers, increasing the breastfeeding peer support offered locally and adopting a clear ‘Breastfeeding Welcome’ policy. This study has demonstrated that a collaborative action research approach can effectively stimulate the development of breastfeeding promotion and support within Children’s Centres, leading to prompt and sustainable changes in practice.