Prevention of malnutrition for children under two (PM2A) is a new approach being used by the United States Agency for International Development (USAID). Since 2010, PM2A has been adopted on a widespread basis in food assistance programs with the aim of preventing chronic malnutrition (stunting) in non-emergency settings. This case study uses mixed methods to document household food sources, insecurity and ration receipt within the context of a multi-year health and nutrition program implemented in South Sudan. Evidence from the program, which included a PM2A component in addition to health, empowerment and household agricultural interventions, indicates that household food security remained poor despite ration receipt. While PM2A is a relatively new strategy and efforts are under way to evaluate outcomes, more evidence is needed to determine the appropriateness of the PM2A approach in highly food insecure contexts and to establish the range of contexts in which PM2A is a choice approach for food assistance programs. Copyright (c) 2013 Longwoods Publishing.