Food allergy and asthma are both atopic diseases and therefore frequently co-exist. Food allergy is common in childhood, affecting approximately 8% of infants. The diagnosis is based on a suggestive history supported by skin-prick testing, serum specific IgE or food challenge. The role of diet in the aetiology of asthma and as a precipitant of exacerbations has been investigated extensively. Many people perceive diet as being an important precipitant of their asthma but objective testing suggests that it is only important in a minority. Meanwhile, there is considerable epidemiological evidence to suggest that there is a link between asthma and food allergy. Food can induce bronchospasm and food allergy has been implicated as a risk factor for life-threatening asthma. Additionally, asthma also seems to be a risk factor for life-threatening food allergy. The mechanism underlying this connection is unclear. The co-existence of food allergy should be considered in any child with asthma. Where food allergy is confirmed, steps should be taken to avoid these foods as this may considerably improve asthma control.