As the prevalence of food allergies in many communities continues to rise, the question of when in infancy to introduce any solid foods, or specific 'more allergenic' foods, as a food allergy prevention strategy has been debated. Observational studies have found that introducing any solid foods prior to 4 months of age was associated with an increased risk of allergic disease. Hence, the current allergy prevention consensus recommendation is that the introduction of any solid foods should commence after 4 months of age. Over recent years, several randomized controlled trials have been conducted to investigate the 'ideal' timing of introduction of some specific 'more allergenic' foods (including peanuts and eggs) into infant diets. To date, the results from three of these trials have determined that there is no reason to delay the introduction of the 'more allergenic' foods into the infant's diet after solid foods have commenced. However, these trials have also highlighted the finding that some infants are sensitized to food allergens before any known ingestion of solid foods. Thus, future research needs to focus on strategies to prevent early-life food allergen sensitization prior to complementary feeding.