A follow-up study of 69 premature infants showed that at a mean age of 11.4 years they had a cumulative incidence of allergic symptoms similar to that reported in unselected series. The 38 premature infants fed exclusively with human milk to the age of four months had more allergic symptoms than the 31 premature infants fed with adapted cow's milk formula from birth (mean number of symptoms 1.6 versus 0.6, p = 0.0025). The excess of symptoms was mostly cutaneous, and often associated with a specific food. In logistic regression models, the only variable with a statistically significant association (standardized odds ratio 3.15, 95% confidence interval 1.12-8.8, p = 0.03) with symptomatic allergy was the type of feed. The frequency of positive skin prick tests and the mean levels of serum IgE and antibodies to cow's milk were similar in the two groups. We infer that food allergy was more common in the group fed with human milk.