Introduction: Food allergy ranks third among all allergic disorders diagnosed in children under fourteen and it is defined as the immunologic response mediated or not by immunoglobulin E against allergens contained in the same source. Objective: To determine which are the most common foods that cause food allergies in pediatric patients from ages ranging between 6 months and 18 years old of the Hospital Nacional Docente Madre Niño San Bartolomé, throughout the months of August to December of 2019 in Lima-Peru. Methods: Observational, cross-sectional analytical study. 113 parents and/or legal guardians of patients between the ages of 6 months and 18 years old participated. A simple random probability sampling was created using the Google forms platform to fill out the food allergy questionnaire. Additionally, by the means of the statistical software Stata version 15.1 the variables of the study were analyzed. Results: From the total of 113 participants in this investigation, the age group most likely to present food allergies is located between 6 and 11 years of age, with predominance in the male gender. 60% of the participants were exclusively breastfed and more than half started complementary feeding between the ages of 6 and 8 months old. Also, the foods that most frequently caused food allergies were raw milk, cooked milk, and cooked eggs. Conclusions: The most frequent foods that produce food allergies are milk and eggs; and among the native foods of Peru the orange predominated. This affected the population between the ages of 6 and 11 years old in a larger scale. Also, the signs and symptoms that presented with greater recurrence were the rejection of foods, bloating, abdominal discomfort, nausea and hives.