The aim of the research was to assess the prevalence and pattern of self-reported adverse reactions to food and food allergies among primary schoolchildren in Vilnius. MATERIAL AND METHODS. Vilnius University was a partner in the EuroPrevall project. A total of 4333 schoolchildren from 13 primary schools participated in the study. Of all 4333 questionnaires distributed, 3084 were returned (response rate, 71.2%). This screening phase was followed by the second (clinical) part with an objective confirmative laboratory analysis of blood samples for the diagnosis of food allergy. For the research purposes, 186 blood samples for IgE were analyzed. RESULTS. Almost half of the children had an illness or a disorder caused by eating food. The prevalence of adverse reactions to food was found to be increasing with age from 6 to 10 years. Food allergy was diagnosed in 16.4% of children. Boys had food allergy more frequently than girls. Diarrhea or vomiting and a rash, urticarial rash, or itchy skin were the most commonly mentioned symptoms. Fruits, berries, and milk and dairy were found to be the most common foods to cause adverse reactions. The most relevant foods for children with IgE-mediated food allergy were cow's milk and hazelnuts. CONCLUSIONS. The prevalence of self-reported food hypersensitivity among primary schoolchildren was observed in almost half of the studied population. Fruits, berries, and milk and dairy were the most common foods to cause adverse reactions among primary schoolchildren in Lithuania. The determined differences in the prevalence of food hypersensitivity and IgE-mediated food allergy and associations with gender and age need further scientific analysis for the development of prognostic and diagnostic tools.