The incidence of food allergies in the pediatric age group is increasing. Food allergy may sometimes cause potentially life-threatening anaphylactic reactions. The purpose of this study was to determine the incidence and clinical characteristics of hazelnut allergy in schoolchildren. A questionnaire was distributed to 20,800 children, aged 6-18 years, attending schools from primary to high. In the first stage of the study, parents were requested to complete the prepared form. A skin prick test (SPT) and prick-to-prick (PTP) test were applied to all children who agreed to participate in the study. Next, a double blind placebo-controlled food challenge (DBPCFC) was applied to subjects with positive skin tests. Children with negative skin tests were administered an open food challenge (OFC). Children with positive results from the OFC took the test again to confirm the results. Of the 20,800 distributed questionnaires, 15,783 (75.9%) were returned. The SPT resulted positive in seven of these and the PTP test resulted positive in eight. DBPCFCs were applied to all 15 children whose skin tests were positive to hazelnut, and these resulted positive in 8. An open oral challenge was applied to all children with negative skin tests and with negative DBPCFC. Finally, eight children were identified as positive for hazelnut allergy, giving an incidence of IgE-mediated hazelnut allergy of 0.051% (95% confidence interval, 0.000219-0.00998). Reaction to DBPCFC was cutaneous in seven children, while skin symptoms and anaphylaxis were observed in one. The incidence of hazelnut allergy in this study was lower than results reported from previous study. Nevertheless, hazelnuts should therefore be considered in cases of food allergy, the most significant cause of allergy in childhood. While dermatological findings predominate in children with hazelnut allergy, care is necessary in respect of severe hazelnut-related reactions seen in children who develop anaphylaxis.