No data on the relationship between allergic sensitization to animal dander and milk allergens are available in literature in adults. Considering the high rate of allergic sensitization to mammals in atopic adults living in Naples area, we aimed to evaluate if sensitization to milk allergens could be a risk factor for these subjects. From 755 consecutive outpatients examined between May 1 2009 and December 31 2010, we selected those with an immediate skin reaction to animal dander and milk. A clinical history including evaluation of pet exposure, the results of skin-prick tests (SPTs) and specific IgE antibodies for milk allergens were recorded. Among three hundred sixty SPT-positive patients, 140 were sensitized to animal dander (38.9%) and 9 to milk allergens (6.4%). Among one hundred forty patients sensitized to animals only one was sensitized also to milk allergens; among 9 milk-sensitized individuals 5 were allergic also to animal allergens (only one to cow dander) while 4 were not sensitized to mammals. Our results suggest that relationship between allergic sensitization to milk and animal allergens is negligible in adult atopic individuals living in urban area of Naples and that high rate of sensitization to animals is likely to be due to other mechanisms such as direct/indirect exposure, and allergen cross-reactions.