Food allergy is common with the prevalence of 5%-7% in Korean children. The development of food allergy is likely to reflect interactions between genetic factors and environmental exposure. To prevent food allergy, early exposure to food allergens through maternal and infant diet have been investigated. Recently, guidelines for primary prevention of food allergy have been updated, and consensus communication on early peanut introduction has been demonstrated. For the first 4-6 months after birth, exclusive breast-feeding is recommended, and if impossible, extensively or partially hydrolyzed infant formula can be recommended in high-risk infants. Introducing complementary foods is recommended between 4 and 6 months of age, even in case of potentially allergenic foods such as egg, milk, and wheat. For the prevention of peanut allergy, early peanut introduction could be better than late peanut introduction in selected high-risk infants. However, infants who developed food allergy should avoid ingestion of specific offending foods.