In the last years, the food security issue came to the foreground again, due to the increase of food demand and of prices for raw agricultural products worldwide. Although it is generally considered that the European Union would not have great problems as regards food security from the supply availability point of view, the income gaps and poverty of certain categories of the population may raise problems with regard to the population's access to food and threaten the food security in certain poorer EU member states, among which Romania is most often mentioned. This paper makes an estimation of the food demand system parameters in Romania on the basis of the AIDS (Almost Ideal Demand System) model. This model was used for the analysis of food demand in different countries of the world, both in the developing countries, for the identification of vulnerable population categories from the food security point of view, and in the developed countries in order to know the population's consumption behaviour. The data from the Household Budget Survey from the 1st quarter of the year 2011 have been used. The food demand system parameters are determined for the households from the urban and rural areas. The expenditure elasticities are higher in the rural area than in the urban area mainly due to the rural population's lower cash incomes.