BACKGROUND:The prevention of food allergy is a key priority for reducing the burden of allergic disease. Environmental exposures modulate the risk of developing food allergy and some of this may be mediated by the infants’ developing microbiome. However, the role of potentially protective environmental exposures, such as pet ownership, are largely un-investigated with respect to food allergy. METHODS:We performed a secondary cohort analysis in the Enquiring About Tolerance (EAT) study, which enrolled 1,303 three-month infants onto a randomised trial to prevent food allergy. A survey elicited domestic animal ownership and participants were examined for atopic dermatitis (AD) at enrolment. Sensitisation to foods and aeroallergens were elicited by skin and serum testing at three, 12 and 36 months. Food allergy status was determined by double-blind placebo-controlled food challenges between one and three years. RESULTS:Food allergy was diagnosed among 6.1% (68/1124) of participants with complete data. No significant relationships were demonstrated between food allergy and caesarean delivery, infections or antibiotic exposure in early life. After adjusting for familial atopic disease, maternal dog/cat sensitisation and participant AD, living with dogs was associated with a 90% reduction in the odds of infants developing food allergy (adjusted Odds Ratio (aOR) 0.10 (Confidence Interval (CI) 0.01-0.71), p=0.02). None of the 49 infants living with at least two dogs developed food allergy, suggesting a dose response relationship (each dog owned aOR 0.12 (CI 0.02-0.81), p=0.03). No relationship was demonstrated between owning dogs or cats and the development of AD. CONCLUSION:Dog ownership in infancy may prevent food allergy. This article is protected by copyright. All rights reserved.