Sudan has been embroiled in civil war continuously for the past 17 years and for all but a few years since its independence from England in 1956. Portrayed in the press as a religious war between the Muslims to the north and the Christian/African population to the south the roots of war are actually much more complicated and include a fight for the vast oil and water resources of the south. Further confusing the issues are tribal conflict, rebel factions fighting for power and northern supported militias raiding and looting. The result has been the systematic destabilisation of the southern people and the almost total absence of infrastructure. In 1989 UNICEF negotiated access with the government in the North and the rebels in the south to the war torn areas of southern Sudan which gave birth to the UN co-ordinated "Operation Lifeline Sudan" (OLS). It has since grown to an alliance of UNICEF, UN World Food Programme (WFP) and approximately 40 NGO's. WFP is the largest single agency and has the responsibility of distributing food to those most vulnerable out of a population of approximately 5.3 million southern Sudanese. Deciding how much, to whom and when budgeted food resources (estimated at 60,000 MT for 2000) should be distributed is the job of the Technical Support Unit, made up of WFP field staff and trainers and seconded food security specialists from Save the Children (UK) (of which the author is one). The Save the Children (UK) - WFP partnership began in 1994 and has continued to this day as a way to provide technical expertise to WFP and provide for more thoughtful and transparent analysis of the food security situation in southern Sudan. Food security is defined by WFP as all people having access at all times to enough food to live an active and healthy life. This study examines the role that local trade and markets play in a household's food security. Specifically, it poses the question: What role does local trade play in the food security of people living in southern Sudan? Access to trade and changes in the role of trade were also examined. Two case studies (Latjor State and Boma Payam) are drawn on for analysis. Data was collected during two field trips made by the author during the UN World Food Programme annual needs assessment in September and October 1999. Information was gathered using unstructured interviews with households, community leaders and other key informants, observation and interviews with food aid experts. Secondary data came primarily from WFP assessment reports. To understand the contribution of trade as a food source in comparison with other foods the Household Food Economy Analysis framework (developed by Save the Children (UK) was used. The data was also analysed to determine the other links between trade and food security, such as access to the means to acquire food (i.e., seeds and tools), nutrition and social capital, (defined as one of the assets vital for sustaining people's livelihoods, the others are: natural, human, physical and financial capital). The study showed that trade has an important impact on the food security of people in terms of access to the implements needed to get food (fishing equipment, tools and seeds for example). Analysis of the food economy data overtime indicated that people were becoming significantly poorer in terms of livestock holdings and that access to trade in the form of local markets and by barter had decreased significantly. This has two negative effects on food security. The first is that it takes away a coping strategy since it limits the extent to which people may trade livestock for grain. Secondly, it has forced a greater reliance on wild food plants as a food source at the expense of milk, which could have negative nutritional implications. The study also showed that decreased access to trade could have a negative impact on the social capital.