The vertical transmission of HIV occurs when an HIV-positive woman passes the virus to her baby during pregnancy, delivery or breastfeeding. The World Health Organization's (WHO) Guidelines on HIV and infant feeding 2010 recommends exclusive breastfeeding for HIV-positive mothers in resource-limited settings. Although evidence shows that following this strategy will dramatically reduce vertical transmission of HIV, full implementation of the WHO Guidelines has been severely limited in sub-Saharan Africa. This paper provides an analysis of the role of ideas, interests and institutions in establishing barriers to the effective implementation of these guidelines by reviewing efforts to implement prevention of vertical transmission programs in various sub-Saharan countries. Findings suggest that WHO Guidelines on preventing vertical transmission of HIV through exclusive breastfeeding in resource-limited settings are not being translated into action by governments and front-line workers because of a variety of structural and ideological barriers. Identifying and understanding the role played by ideas, interests and institutions is essential to overcoming barriers to guideline implementation. Copyright © 2012 John Wiley & Sons, Ltd.