52 security in Burundi and to highlight certain factors of vulnerability. The notion of food security is defined in terms of availability, of access and use of food, that of vulnerability in terms of exposure to risk and of adjustment capacity. This survey made it possible to estimate the number of households in a state of serious food insecurity at 63,900 namely 4.8% of the country’s households, and that of the households in a state of moderate food insecurity at 302,700 namely 23%. Moreover the number of children aged less than 5 in a situation of moderate malnutrition is said to be 26.5% and that of children in a situation of severe malnutrition is 9.2%. More precisely, 52.7% of these children showed a delayed growth rate and 8.4% showed a weight deficiency in relation to their height. The factors determining food insecurity relate to the wealth of the household and to the possession of assets, of access to land and to the occupation status, or even to the surface area of the farmland. It would appear that the households headed by a woman are more prone to food insecurity and that women diversify their production less and rarely cultivate export crops. In terms of household profiles, the survey made it possible to isolate 5 types of households which are especially at risk. In the first instance, the households referred to as « marginal », characterized by an elderly head of household, who is little educated, is socially and geographically isolated, with an extremely low average income made up of 60% of transfers and pension payments, with the balance coming from subsistence farming. The second category which is most affected is that of the landless farmers who live off their labour power for up to 84% of their income, are dependent on the market for food supplies and do not earn enough to invest in productive assets to improve their condition. The third group is made up of brewers who draw two thirds of their income from the activities of 60 breweries, and the rest from agriculture. Finally the largest group of actual farmers who draw 90% of their income from agricultural production, representing one third of the total population but whose average income is just half of the average national income.